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OUTLINE - A SHORT MASONRY GUIDE

(Revised, 2013)

A. MASONRY MORTAR MATERIALS

1. Masonry Sand

2. Admixtures

3. Masonry Cements

4. Mortar Cement

5. Portland and Blended Cements

6. Hydrated Lime

7. Water

B. MASONRY MORTARS

1. ASTM C 270, Types O, N, S, M

2. ASTM C 270, Proportion Specification and, Property Specification

3. Proportions

4. Retempering

5. Temperature Effects and Effects of Weather Conditions

C. MIXER

1. Type

2. Mechanical Condition

3. Mixer Cleanliness

D. MORTAR MIXING

1. Batching Materials

2. Mixing Time

3. Consistency

E. MASONRY UNITS

1. Absorption

2. Initial Rate of Absorption (IRA) - ASTM C 67

3. Initial Rate of Absorption (IRA) At the Time of Use

4. Variable Rates of Absorption (IRA) At the Time of Use

5. Impurities

F. WORKMANSHIP

1. Spreading of Mortar

2. Mortar Bed

3. Laying of Units

4. Head Joints

5. Tooling of Mortar Joints

6. Cleaning of New Masonry Work

G. MASONRY PROBLEMS

1. Wall Cracking

2. Efflorescence

3. Color Variations in Joints, and/or, Within a Joint

4. Color Variations in Walls, or, Sections of a Wall

H. FIELD TESTING of MASONRY MORTAR

1. ASTM C 780

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A. MASONRY MATERIALS

1. Masonry Sand Since masonry sand will occupy the greatest volume of any of the materials in a given batch of mortar, its characteristics will reflect on the characteristics of the mortar. The gradation of the sand has an effect on the air content, water retention, board life, workability, stickiness, spreadability, plasticity, and, board life of the fresh mortar. The effects on the hardened mortar include compressive strength, bond strength, extent of bond, and, color. Even if a sand has a gradation that falls within the limits of ASTM C 144 [see page 20], the variation allowed by C 144 allows a great variation in the gradation of a sand. The F. M. of the sand can range from 1.75 to 2.93, and still be within the gradation limits of C 144. If the sand varies from one extreme of allowable gradation to the other during a job, the mortar properties will vary also. To further confuse the issue, ASTM C 144 will still allow a sand not meeting the gradation requirements to be used, if when tested in mortar as per ASTM C 270, the mortar meets the property requirements of C 270, which are; water retention, 28-day compressive strength, and, in some cases, air content. The moisture content of the sand at time of use can have an effect on the actual amount of sand in a batch of mortar. Loose sand with varying amounts of free surface moisture will occupy differing volumes. This is called "bulking" [see page 21] and usually occurs when the sand has been "moved". Bulking usually peaks with about 5% free moisture on the sand and can range from a volume increase of about 17% with coarse sand to over 35% with fine sand. Due to this bulking, measuring sand by a shovel can result in over sanded or under sanded mixes. A good mixer operator can usually tell from experience when the mix is proper by the volume occupied by the batch in the mixer. Typically a mason will complain when the mix is over sanded, or under sanded, due to the effect on workability properties. Dirt, silt, and sand particles passing the 200-mesh sieve can make an exceptionally good working mix due to the excess of these very fine particles. This very fine material can also cause an excessive water demand leading to a reduction in the compressive strength of the mortar, and a reduction in the mortar air content. These fine materials could also bring about shrinkage of the hardened mortar. These fines can also have a serious effect on the color of the hardened mortar, and, when these fines vary from batch to batch, color variations can also occur. Being the majority constituent in a volume of mortar, the temperature of the sand has a direct bearing on the temperature of the mortar. Sprinkling of the sand pile in hot weather may be impractical in many cases due to the resulting mud from the water run-off, but it can lower the sand temperature. A white or reflective cover to reflect the suns rays can be a help. A canopy or shaded area will also help hold the sand temperature down.

The sand should be heated when the ambient temperature approaches 32 oF. In below freezing

temperatures, frozen lumps of sand should be thawed before the sand is put into the mixer.

In cold weather, a black or dark cover, placed over the sand pile may help, as they would absorb

some heat from the sun. However the sand is heated or kept warm, the sand pile should be treated so the sand being used is at a uniform temperature.

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2. Admixtures Mortar admixtures added at the job site may be calcium chloride, ethylene glycol, air entraining agents, retarders, water-repellency agents, and, coloring agents. There are known cases of "dish washing" soaps being added to mortar. Most of these are totally unnecessary as most all producers of masonry cement add the proper materials to the cements at the time of manufacture. Calcium chloride is sometimes used in mortar with excellent results, other times problems can arise due to the calcium chloride being instrumental in causing corrosion of steel in contact with the mortar, and corrosion or staining of aluminum in contact with the mortar, especially if moisture is present. Discolored or darkened mortar joints may also come from the use of calcium chloride in the mortar. Ethylene glycol, an antifreeze, was shown in one study to have extremely detrimental effects on the compressive of mortars when added in amounts exceeding 10% by weight of cement. The use of ethylene glycol does not appear to have any beneficial effect on the mortar when added in amounts less than 10% by weight of cement. The use of ethylene glycol was discouraged in this study. The addition of air-entraining agents at the job site should be discouraged due to the likely possibility of an excessive air content in the mortar. Excessively high air contents can reduce compressive strength, flexural bond strengths, and, the durability of the mortar. Masonry cements are manufactured to meet the air content requirements of ASTM C 91, and to make mortars meeting the requirements of ASTM C 270. The addition of retarders on the job site is not a common practice. The use of a job site added retarder would typically be offset by the stiffening of the mortar due to the evaporation of mix water due to ambient weather conditions. Water-repellent materials or "waterproofing" agents are sometimes added at the job site. There is some disagreement as to the actual effectiveness of these added materials. Masonry practices and workmanship appear to have the greatest effect on the "watertightness" of a wall assembly. Colored mortar may be obtained by the use of pigments added at the job site, or, preferably, through the use of a preblended colored masonry cement. The use of preblended colored masonry cement has the distinct advantage of containing all materials in one package with no weighing or measuring of pigments required at the job site. Adequate mixing time is necessary to disperse all ingredients throughout the mortar mix, and is especially critical with job site added pigments. Pigments used for colored mortar should not contain any dispersant that will affect the hydration of the cement. The pigments used should meet the requirements of ASTM C 979, Pigments for Integrally Colored Concrete. The final color of the mortar in the joints is affected by the proportions used; the sand color; amount of water in the mix; retempering water added; and, mortar stiffness at time of tooling. Retempering of colored mortars (if it should be allowed at all) should be done with caution and common sense.

3. Masonry Cements Most masonry cement producers manufacture masonry cements meeting the requirements of ASTM C 91, "Standard Specification for Masonry Cement". [see page 22] These are usually in three types, Type N, Type S, and, Type M. Some producers do manufacture a "combination" product which they may call "High Strength", and is formulated to meet the requirements of both a Type S and Type M. ASTM C 91 covers only the masonry cements, not mortar or mortar properties, ASTM C 270 covers mortars. C 91 masonry cements are for making masonry mortars, of their respective types, of C 270 mortars. When using a masonry cement of the types listed to make C 270 mortars of the same type, no further additions of portland or blended cements, or, hydrated lime is necessary, or desirable. Masonry cements typically contain interground air-entraining agents; plasticizers; boardlife extenders; and, water repellency agents. They are formulated so no further additions of admixtures are needed at the job site to make good mortar. Masonry cements are required to meet the requirements of C 91, for their respective type, for fineness; autoclave expansion; setting times; compressive strength; air content; and, water retention. Essentially, C 91 is a performance specification in that one can use what raw materials will do the job and meet the requirements of C 91. The main difference in the three types of masonry cement is in the compressive strength requirements of C 91. The minimum 28-day compressive strength requirements

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are; Type N = 900 psi; Type S = 2100 psi; Type M = 2900 psi. These compressive strength requirements are for the masonry cements tested with Standard and Graded sands meeting the requirements of ASTM C 778. These mixes are made in the laboratory, proportioned, mixed, and tested according to C 91.

4. Mortar Cement For some time, many masonry cements were called "mortar cements" by the manufacturers and users, and some companies even had the words "Mortar Cement" printed on their bags quite prominently. Now there actually is a "Mortar Cement",[see page 22], as defined by the UBC (Uniform Building Code) and ASTM as C 1329. This Mortar Cement is in the UBC as, " Uniform Building Code Standard No. 24-19, Mortar Cement". The compressive strengths, No. 325 fineness, Autoclave Expansion, Setting Time, and, Water Retention, are the same as is in ASTM C 91 for masonry cements, as are the three (3) types, (N, S, &, M) The Mortar Cement has a lower maximum allowable air content, than C 91 masonry cements, and has

a minimum flexural bond strength required, and has a list of restricted materials as ingredients in the cement. The flexural bond strength requirement is a "new" one for a cementitious material, and, so far is only required by the UBC for Mortar Cement, in ASTM as C 1329, Mortar Cement. A table is at the end of this paper, which gives the requirements of both C 91 for Masonry Cements, c 1329 for Mortar Cements, and, UBC 24-19 Mortar Cement.

5. Portland and Blended Cements Neither portland cement nor blended cement is made strictly for the purpose of using in masonry mortar, as is masonry cement and mortar cement. The ASTM Specifications for portland and blended cements are aimed at serving the needs of the concrete and concrete products producing industry. Both portland and blended cements are produced to meet the requirements of the applicable ASTM Specification. Portland cements, in several types, are to meet the requirements of ASTM C 150, "Standard Specification for Portland Cement, Blended cements are to meet the requirements of ASTM C 595, "Standard Specification for Blended Hydraulic Cements. ASTM C 150 covers eight (8) types of portland cement: Type I - For use when the special properties specified for any other type are not required. Type IA - Air-entraining cement for the same uses as Type I, where air-entrainment is desired. Type II - For general use, more especially when moderate sulphate resistance or moderate heat of hydration is desired. Type IIA - Air-entraining cements for the same uses as Type II, where air-entrainment is desired. Type III - For use when high early strength is desired. Type IIIA - Air-entraining cement for the same use as Type III, where air-entrainment is desired Type IV - For use when a low heat of hydration is desired. Type V - For use when high sulphate resistance is desired. ASTM Definition of portland cement : A hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulphate as an interground addition. In contrast, the ASTM definition for ASTM C 91 Masonry Cements is: A hydraulic cement, primarily used in masonry and plastering construction, consisting of a mixture of portland or blended hydraulic cement and plasticizing materials (such as limestone, hydrated or hydraulic lime) together with other materials introduced to enhance one or more properties such as setting time, workability, water-retention, and durability. Portland or blended cements are never used alone in masonry mortar, but are used in combination with hydrated lime and, occasionally with masonry cement or mortar cement. ASTM C 595 has five classes of blended cements listed and various added provisions for different types:

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Portland Blast-Furnace Slag Cement, Types IS, MS, A, MH. Portland-Pozzolan Cement, Types P, MS, A, LH. Slag Cement, Type S Pozzolan-Modified Portland Cement, Types I(PM), MS, A, MH. Slag-Modified Portland Cement, Types I(SM), MS, A, MH.

6. Hydrated Lime The typical hydrated lime used in masonry mortar today meets the requirements of ASTM C 207,"Standard Specification for Hydrated Lime for Masonry Purposes". C 207 lists four (4) types of lime: Type N - Normal hydrated lime for masonry purposes. Type S - Special hydrated lime for masonry purposes. Type NA - Normal air-entraining hydrated lime for masonry purposes. Type SA - Special air-entraining hydrated lime for masonry purposes. Type S is the most commonly used of these four types. The basic difference between Type N and Type S is the allowable percentage of unhydrated oxides. Type N has no maximum limit while Type S has a maximum limit of 8%. An air-entrained hydrated lime should not be used in conjunction with an air-entrained portland or blended cement in masonry mortar due to the possibility of generating an excessively high mortar air content.

7. Water Usually, water that is suitable for drinking purposes is suitable for use in masonry mortar. Any mix water used should be free of any harmful amounts of acids, alkalies, or organic materials. Some potable waters may contain appreciable amounts of soluble salts such as sodium and potassium sulphate. These salts can contribute to efflorescence. Water containing sugar can retard the set of mortar. Water containing high amounts of chlorides can lead to corrosion problems.

B. MASONRY MORTARS

1. Types O, N, S, M ASTM C 91 recognizes only three (3) types of masonry cements, and ASTM C 1329 recognizes three types of Mortar Cement, but ASTM C 270 recognizes four (4) types of mortars. In the mortars, the difference is mainly in the minimum compressive strength requirement.

2. ASTM C 270, Standard Specification for Mortar for Unit Masonry C 270, [see page 23], recognizes four (4) types of mortars, Types O, N, S, & M in three (3) "kinds" of mortars, and two (2) methods of specifying mortars. The three "kinds" of mortar are; portland

cement/hydrated lime, (PCL), masonry cement, (MC), and mortar cement mortars (MtrC). The two (2) methods of specifying mortars are the "Proportion Specification" and the "Property Specification" method.

The basics of the C 270 Proportion Specification for MC Mortars are: 1. The masonry cement content is given. 2. The sand content can vary within the range given. 3. No compressive strength, air content, etc., values are given, only the proportions must be followed.

The basics of the C 270 Proportion Specification for MtrC Mortars are: 1. The masonry cement content is given. 2. The sand content can vary within the range given. 3. No compressive strength, air content, etc., values are given, only the proportions must be followed.

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The basics of the C 270 Proportion Specification for PCL Mortars are: 1. The portland or blended cement content is fixed. 2. The hydrated lime proportions can vary within the range given. 3. The sand ratio can vary within the range given. 4. No compressive strength, air content, etc., values are given, only the proportions must be followed.

The basics of the C 270 Property Specification for MC Mortars are: 1. The masonry cement content is not given. 2. The sand content can range within the range given. 3. The mortar must meet the requirements for compressive strength, water retention, and, in some cases, air content.

The basics of the C 270 Property Specification for MtrC are: 1. The mortar cement content is not given. 2. The sand content can range within the range given. 3. The mortar must meet the requirements for compressive strength, water retention, and, in some cases, air content.

The basics of the C 270 Property Specification for PCL Mortars are: 1. The portland or blended cement content is not given. 2. The sand content can range within the range given. 3. The mortar must meet the requirements for compressive strength, water retention, and, in some cases, air content. All C 270 testing MUST be done in the laboratory, using the materials, and proportions to be used on

the job. MORTAR SAMPLES TAKEN IN THE FIELD FROM JOB SITE MIXED MORTAR DO NOT

HAVE TO, and ARE NOT EXPECTED TO MEET THE REQUIREMENTS OF THE PROPERTY

SPECIFICATION OF C 270! Often overlooked in C 270, is the Referenced Documents Section, which refers to other ASTM Standards, Test Methods, and/or Specifications which must be met in order for the mortar to meet C 270. These include mortar ingredients, test equipment, test methods, and, recommended practices. Simply stated, the Proportion Specification only requires the Mason Contractor to supply mortar for a job that fits within the proportion range given, using materials that meet the applicable requirements. The Property Specification requires the mortar materials be laboratory tested to insure the mortar meets the minimum or maximum requirements of C 270, and the cementitious materials to sand ratio be within the range given. Another ASTM Standard, C 144," Standard Specification for Aggregate for Masonry Mortar", refers to C 270 in the following manner in Section 4.4. It states, "When an aggregate fails the gradation limits specified in 4.1 and 4.2, it may be used provided the mortar can be prepared to comply with the aggregate ratio, water retention, and compressive strength requirements of the Property Specification of Specification C 270. An often-overlooked portion of C 270 is Section 6. Construction Practices. This section covers such items as: Storage of materials on the job site; Measurement of materials for the field mixed mortar; Mixing of the field mixed mortars; Tempering of field mixed mortars; and, Climatic conditions during the job. Section 7 of C 270 is a very important, and, overlooked section, portions of it state the following: 7. Specification Limitations 7.1 Specification C 270 is not a specification to determine mortar strengths through field-testing.

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7.2 Test Method C 780, is acceptable for preconstruction and construction evaluation of mortars for plain and reinforced unit masonry. 7.3 Tests of Hardened Mortars - There is no ASTM method for determining the conformance or nonconformance to Specification C 270 by tests on hardened mortar removed from a structure, but such standards are available to determine some hardened mortar properties. Note 7 - Where necessary, testing of a wall or a masonry prism from the wall is generally more desirable than attempting to test individual components.

3. Proportions The proportions of the mortar mix, the cement to aggregate ratio, and the water/cement ratio have a great effect on the workability and performance of the mortar. Low sand contents can lead to a very rich, sticky, not very workable mix, be difficult to spread properly, have a high shrinkage potential, and a short "board life". High sand contents can lead to a large reduction in compressive strength, poor bond, poor workability, harsh mix, and, low durability. The water content should be as high as possible without the mix being soupy or sloppy. The wetter the mix, within reasonable workability limits, will increase the bond of the mortar to the masonry units. Adequate water content is necessary to allow water for hydration of the cement after some water is lost due to absorption of the units and evaporation. A mix using the minimum amount of water resulting in a very stiff mix, may result in poor bond with the masonry units, short "board life", inadequate plasticity, and dryout of the mortar in the wall.

4.Re-tempering (Tempering) Retempering of mortar is an accepted practice, however it should be with reason. During hot, dry, and windy weather, retempering of mortar on the board is usually done to replace water lost by evaporation. In many cases, the mortar on the board is used before it requires retempering. Under normal conditions, one or two retemperings cause no harm, but reason and common sense must be used. When a large batch of mortar is mixed for an extremely slow mortar consumption job, many retemperings may take place to maintain the consistency of the mix on the boards, this can lead to low strengths, and the possibility the excessively retempered mortar may show up in the wall as very light colored joints. Colored mortar should never be re-tempered. Extreme caution as severe changes in the water/cement ratio can have very definite effect on the color and brightness of the mortar joints. The safest way to avoid problems that result from retempering, especially excessive retempering, is to mix only as much mortar as will be used before retempering is necessary. This is especially true with colored mortars.

5. Temperature Effects and Effect of Weather Conditions It is a well established fact that the hydration rate of portland cement and portland cement based products is greatly affected by temperature changes. For both PCL and MC masonry mortars, the higher the ambient and mortar temperatures, the higher the ambient and mortar temperatures, the faster the hydration reaction takes place with resulting quicker set times. For both PCL and MC masonry mortars, the lower the mortar and ambient temperatures, hydration takes place much slower with the set time being longer. There are several factors involved in hot weather, which affect the mortar on the board, and in the wall. 1. More water is usually required to maintain workability. 2. Initial and Final set will occur earlier, and evaporation rates of water from the mortar is usually at higher rates. 3. Masonry units, typically being warm or hot, usually will have a faster rate of absorption. 4. Rapid drying of the mortar joint, especially at the exposed face, is harmful.

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There are several steps that can be taken to minimize the effects of high ambient temperatures and help keep the mortar temperature as low as possible, or at least to minimize the heat gain of the mortar materials. 1. Store all materials in a shaded area, open to cooling breezes. 2. Where the mix water is kept in a barrel or drum, paint the drum white or aluminum color to help reflect the heat. Do not use a black or dark colored container. 3. Keep the water hose used to fill the mix water container out of the direct rays of the sun. 4. When running water through the hose to fill the mix water container, run the hot water out on the ground before filling the container. The hose, if laying in the sun, acts just like a solar water heater. 5. If practical, sprinkle the sand pile to allow evaporation of water to help cool the sand. PCA reported that when evaporating, one (1) gallon of water would cool one (1) cubic yard of sand 20

of at the surface

of the sand pile. 6. Cover the walls immediately after construction to prevent the loss of moisture. 7. The use of windscreens or fog sprays can reduce the amount of evaporation of moisture from the wall. 8. Before each use, flush the mixer, wheelbarrows, mortar buggies, mortar tubs, and mortarboards with cool water. Cold weather brings about an entirely different set of circumstances than hot weather. Cold weather masonry construction may continue even at temperatures below freezing, but steps have to be taken to prevent unwanted problems. The first step is the comfort of the masons on the job. Productivity suffers when a worker is uncomfortable due to cold temperatures. Before starting a job in cold weather, or a job that will continue into cold weather, proper planning must be done to insure a successful job. Extra costs can be involved with winter construction work, but some of the costs may be negated by an earlier completion date, The following table of recommendations as to when to heat the materials, what materials to heat, when to protect, how to protect, and, the desired material temperature range, these recommendations should be followed for cold weather masonry construction projects. Admixtures sold for cold weather masonry mortar should be used with caution, and only after tests have proven they have no detrimental effects on the mortar. Some so-called "anti-freeze" admixtures must be used in such high quantities to lower the freezing point of mortar that they have a very detrimental effect on the mortar. So-called anti-freeze compounds are not recommended for masonry mortar as they seriously reduce the compressive strength of the mortar. One of these "anti-freeze" materials, ethylene glycol, is sold as an anti-freeze for RV waste water systems, and has been frequently used as a mortar "anti-freeze", it seriously reduces the compressive strength of mortar. The most commonly used mortar accelerator is calcium chloride, but it should be used with caution, if used at all. Calcium chloride in mortar can lead to increased mortar shrinkage, efflorescence, and, corrosion of metal embedded in mortar, especially when subjected to moist conditions. There are non-chloride accelerators available from the major admixture suppliers and, if used, they should be tried under job conditions prior to use. All materials on the job site should be well protected from rain and snow, shelters may be desirable for the protection of the mixer, cement, and sand pile. Any method used to heat mortar materials should provide a source of consistent temperature to the mortar materials throughout the day. Water is the easiest material to heat, its temperature should remain consistent throughout the day. Sand that heated over an embedded pipe should be turned frequently to attempt to maintain a reasonably consistent temperature. Cement and masonry units can be stored inside a heated shelter to maintain temperatures above freezing, Temporary shelters may be built to protect the portion of the building where the masons are working; the masonry work just completed; or, the entire structure. Some additional points for cold weather masonry work are: 1. Have mortar at proper temperature. Never below 40

oF, and, never over 120

oF.

2. Have units at proper temperature. If the units are too cold, they can cause a drastic reduction in the mortar temperature due to the thinness of the mortar joints, which can loose heat quite rapidly. Conversely, units which are too hot can cause a flash set of the mortar at the mortar/unit interface.

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3. Never lay mortar on a frozen surface, ice covered surface, or snow covered surface. 4. To avoid excessive cooling of heated mortar before use, mix smaller quantities so the mortar does not cool off too fast or too much. 5. Cover the top of the wall at the end of the day to prevent water, snow, or ice entry into the wall and cavity.

RECOMMENDATIONS for COLD WEATHER MASONRY CONSTRUCTION

AIR TEMP.

oF

CONSTRUCTION REQUIREMENTS Heating Materials

PROTECTION

Above 40 Normal Masonry Procedures Cover walls with plastic or canvas at the end of the workday to prevent water from entering the masonry

Below 40 Heat mixing water. Maintain mortar temp between 40 and 120 until placed

Cover walls and materials to prevent wetting. Covers should be plastic or canvas.

Below 32 In addition to above, heat the sand. Frozen sand must be thawed.

With wind velocities over 15 mph, provide windbreaks during the day and cover walls and materials at the end of the workday to prevent wetting and freezing. Maintain heat above 32 oF by using auxiliary heat or insulating blankets

for 16 hours after laying units.

Below 20 In addition to above, dry masonry units must be heated to 20

oF.

Provide enclosures and supply sufficient heat to maintain enclosure above 32

oF for 24 hours

after laying units.

Adapted from guide specifications of the International Masonry Industry All-Weather Council (One old time rule of thumb says: "when you are comfortable, the mortar is comfortable".)

6. Consistency Each batch of mortar should be proportioned, placed in the mixer, and, mixed the same time to give a consistent mortar to the masons. A recommended batching and mixing procedure is as follows: 1. Add about 3/4 of the water. 2. Add about 1/2 the sand. 3. Add all of the cement, or, cementitious materials. 4. Mix briefly. 5. Add the remaining sand. 6. Add final water to give desired consistency. Mixing action is usually the most effective when the mixer is charged to full design rated capacity. Overloading a mixer can lead to an under mixed or poorly mixed mortar. Undermixing can lead to a very non-uniform mortar. Improper batching and mixing procedures can turn perfectly good mortar materials onto a poorly performing mortar. Too short of a mixing time is usually the most common mixing problem encountered.

C. MASONRY UNITS

Any and all masonry units used in masonry construction should meet the applicable ASTM and job specification requirements. ASTM has two (2) standards pertaining to clay or shale masonry units, and three (3) for load bearing concrete masonry units. Each one of these standards has two or more designations or classes of units. Each class has a maximum allowable absorption specified. The more severe the exposure the unit is exposed to, (in place), the lower the allowable absorption. The absorption of concrete units is based on

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soaking the units for 24 hours in water at 60 to 80 oF. The clay or shale units have a combination of

submersion in boiling water for five (5) hours, followed by soaking in water at 60 to 86 oF for the

specified time.

1a. Absorption - Clay or Shale Building Brick *** There is apparently a relationship between the durability of brick in climates undergoing freeze/thaw cycles and the total absorption of the units. This relationship has been difficult to define with precision, as the brick in place have to be wet before being affected by freezing temperatures. There are reported cases of brick that do meet the ASTM requirements that have failed in service, and, cases of brick not meeting the ASTM requirements that have performed satisfactorily in freeze/thaw exposures. This is another case of where laboratory test results do not necessarily hold true for field results. The durability of the units in place is apparently related to the total absorption of the unit, the percent of total absorption at the time of freezing, the rate of temperature drop, and, the size of the pore structure of the unit. Perhaps the best guide is the service record of a given unit in the climatic area in which it will be placed into service.

1b. Absorption - Concrete Masonry units Water absorption and density are related in concrete masonry units and affect the construction, insulating, acoustical, appearance, porosity, and, painting characteristics of the units. As the density of the unit increases, the absorption lowers. Units with high absorption will pull water from the mortar joints rapidly. Mortar dry-out in the joints of concrete masonry work is not uncommon in hot, dry weather. Rapid stiffening of the mortar in the joints, brought about by the highly absorptive units, also creates problems for the mason when trying to place, level, and align the units. There is no ASTM specification relating to the IRA of concrete masonry units. Typically, a concrete unit with low absorption will also have a lower percentage of drying shrinkage. Due to the fact that concrete masonry units expand when wet, and, shrink upon drying, they should not be wetted before placing in the wall.

2. Initial Rate of Absorption - Clay & Shale Masonry Units This only applies to clay and shale masonry units. There is no ASTM Specification or Standard with either minimum or maximum limits on IRA, ASTM C 67, contains a method of testing the units for the IRA values. The Initial Rate of Absorption (IRA) relates the weight of water, per square inches of area, that a unit will absorb in a given time. This is expressed the amount of water, in grams, the unit will absorb per 30 in

2 of

unit. This is a laboratory test ran on oven dry units, and may not relate to the IRA of the units at time of use. It is recommended that brick having IRA's over 30 grams per 30 in

2. be wetted before being placed into

use. Some masons may dip a brick into water as he is ready to place it into the wall, but it is recommended that a cube of high IRA brick be thoroughly saturated from 3 to 24 hours prior to use. If dry, high IRA brick are placed into the wall, poor extent of bond, poor bond strength, and possibly, dry-out of the mortar may occur. This may also result in a leaky wall that has little resistance to wind driven rain.

3. Initial Rate of Absorption at Time of Use Depending on weather conditions, brick packaging, and storage of units, the laboratory IRA values may or may not relate to the actual IRA of the brick at the job site. There is a simple and quick "Rule of Thumb" IRA test that can quickly provide information as to whether or not to prewet the units. The procedure is as follows: 1. Pull as many units as desired from the brick on hand. 2. Using a 25-cent piece, draw a circle around the coin.

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3. Trace around the circle with a wax crayon. 4. Using an eyedropper, quickly place 20 drops of water in this circle. 5. Time the seconds it takes the unit to absorb the water. 6. If the unit takes under 90 seconds to absorb the water, it should be wetted before use. If it takes over 90 seconds, the unit is okay to use as is. While the laboratory test from C 67 gives valuable information, this quick field test is of great value because it gives you the information quickly and on the units at the place of use.

4. Variable Rates of Absorption When units have widely differing IRA's, such as some blends of brick, are used in a wall, two problems may be readily apparent.

1. When the mortar bed is spread over the units with widely different IRA's, some of the mortar may stiffen rapidly, and not give good bonding. This can allow a weak spot in the wall and allow water to enter the wall.

2. When units of widely differing IRA's are used together in a wall, the proper tooling time for one portion of mortar in that joint may not coincide with the proper tooling time in another portion of the joint. This creates quite a problem for the mason who is trying to tool the joints so they all have the same finished appearance. This situation can lead to quite a color variation in areas of the finished wall. A close visual examination will reveal areas of the joints with a "slick" finish, and other areas may exhibit a "tearing" of the mortar caused by the tooling of a very stiff mortar.

5. Impurities and/or Contamination Masonry units stored in contact with the ground can absorb materials from the ground, when wet, can lead to efflorescence problems with the structure, and, in some cases, efflorescence may occur before the units are used. Efflorescence causing compounds can be contained in the soil, and in the ground water which has percolated these compounds to the surface where they may be absorbed by the units. Polluted rainwater can fall on uncovered units during storage. Mud and dirt from construction activities may cover the units stored at the job site. If mud and dirt coat the units, they should be cleaned prior to use as the coating may cause of bond. Masonry units stored at a job site should always be stored off the ground, not in standing water, and covered to protect them from rain, snow, ice,dirt, dust, mud, paint, or any material that may affect their appearance or performance in the wall.

D. WORKMANSHIP

The mortar and masonry units used on a job may be of the highest quality, but if poor

workmanship is used in assembling these materials, a poor quality job will be the result.

Craftsmanship, common sense, and dedication to doing the job right are required of a mason.

1. Spreading of mortar A good workable mortar with good plasticity and spreadability should be supplied to the masons on the job. The mason should be able to spread a trowel full of mortar evenly, without gaps that have to be, or, should be filled in.

2. Mortar Bed The amount of mortar used should be an adequate amount to allow full and even contact between the mortar and unit. An excess of mortar should squeeze out from between the units, this is one sign that an adequate of mortar is in the joint. The mortar should never be placed on frozen, ice covered, snow covered, or dirty units or base.

12

In hot weather, the length of the mortar bed should only be long enough to remain plastic before units are placed on it. Deep furrowing, and possibly any furrowing, should not be allowed. Deep furrowing can prevent full contact of the unit bedding face and the mortar, and create channels for water entering the wall to travel through. An excessive amount of mortar must not be allowed to fall in the air space between the veneer units and the back-up. This can plug weep holes and prevent water from exiting the wall properly. It must be kept in mind, a brick veneer wall is called a "drainage wall" as some water is expected to penetrate the veneer from the front. But, with proper materials, design, and workmanship, this water is expected to drain harmlessly down the backside of the veneer until it comes to the flashing, and is directed to the exterior of the building through the weepholes

3. Laying of Units The units should be placed into position and adjusted as quickly as possible. This is very important if units with a high IRA are used. Any units that are in place and have to be moved or removed should have the surrounding mortar removed and replaced also. Any unit that is too low or out of line should be replaced as well as its surrounding mortar. Any mortar bed that has stiffened prior to the units being placed on it should be removed and replaced. If a cavity wall is being built, excess mortar should not be allowed to fall into the cavity. Units should not be moved once they are placed into their final position. Excess mortar which squeezes out should be cut off cleanly with a trowel, without tearing the face of the joint or smearing mortar on the units.

4. Head Joints Full head joints are required for continuity of bond, structural integrity, and, water resistance of a wall. Partially filled head joints do not allow for full contact between the mortar and adjacent units. This joint must be full with an excess of mortar squeezing out for it to be effective. This is a very important joint, but a full head joint is often ignored on brick work.

The UBC, (Uniform Building Code), states, in Section 2404, Construction, Solid masonry units shall

have full head and bed joints. This is also stated in the Indiana Building Code. ACI 530.1-92/ASCE 6-92/TMS 602,"Specifications for Masonry Structures", states the following in

Section 2. 3. 3. 3 Placing mortar and units, (e) Solid Units - Unless otherwise required, solidly fill bed

and head joints with mortar and:

1. Do not fill head joints by slushing with mortar. 2. Construct head joints by shoving mortar tight against the adjoining unit. 3. Do not deeply furrow bed joints. In essence, the long standing recommendation for fully filled head joints is the "law" in most areas.

5. Tooling of Mortar Joints This is essentially the final step in quality workmanship as far as the mason is concerned. The time of tooling, and the kind of tool used to "dress out" these joints plays a very important part in the walls

resistance to water penetration of the wall, and the appearance of the wall. Only Concave, Grapevine,

and, Deep "V' joints should be used on masonry exposed to rain, snow, ice, and areas subjected to freeze/thaw cycles. Raked joints, which are becoming more heavily used, should not be used in areas subjected to heavy rainfall, ice, or, snow. The raked joint creates a ledge on the masonry units that will catch and hold rain and snow, and do not work well where water permeance is a concern.

13

Concave and "V" joints, when tooled properly, exhibit a compacted dense mortar at the exposed surface that is better able to shed rain and snow, and compacts the mortar against the adjacent units, which helps with the bond at the exposed surface, which helps the water resistance of the wall. The consistency, or wetness, of the mortar at the time of tooling has a great effect on the final color of the mortar joint. The wetter the mortar is when it is tooled, the lighter the color of the joint. The stiffer the mortar is when tooled, the darker the color of the joint. This can have a serious effect on the finished color of the joints on a job using colored mortar. Since the setting and/or the stiffening rate of the mortar in the joints is influenced by many factors, such as; water retention of the mortar; IRA of the units; mortar temperature; unit temperature; ambient temperature; wind velocity; relative humidity; and, wetness or consistency of the mortar, the proper tooling time can vary from day to day, and within one day. Experience and common sense should be the judge when it comes to selecting the proper tooling time. The " Rule of Thumb" is that when the mortar in the joint is thumbprint hard, the joints are ready to be tooled. Regardless of when the tooling is done, all joints on a particular job should be tooled on mortar of the same consistency or stiffness. Joints struck early have an excess of paste at the surface, and may not have good bond with the units due to the wetness of the mortar. Joints tooled too late may sometimes exhibit a tearing of the surface of the mortar due to the stiffness of the mortar and its resistance to the tool moving over the surface.

6. Cleaning of New Masonry Work The materials and methods used in cleaning new masonry work can have a definite effect on the final appearance and durability of the finished wall. Preliminary cleaning will include the scraping off of chunks of mortar and mortar splatters that are stuck to the masonry units, doors, windows, trim, etc. The tool used to scrape mortar off should always be made of a material that is softer that the material the mortar than the material the mortar is adhered to, this will prevent the tool from defacing or marking the units or other materials during cleaning. This scraping should always be done before any other cleaning is attempted. Dry brushing may be used where only a light scum is on the units which was left from splatters of mortar on the units. Washing with water, accompanied by brushing, may do a satisfactory job of cleaning on many walls. If a diluted, job mixed acid is to be used, the solution should always be tried on an inconspicuous section of a wall. Dilute muriatic acid solutions should never be used on walls built with units containing either manganese or vanadium, and should be used with caution on any masonry work. When a dilute muriatic acid solution is used, it is very important the wall be completely saturated with water before the application of the acid solution, this solution should never be placed on a dry wall. The solution should never be allowed to dry on the wall, but must be completely flushed from the surface. Fortunately, there are many good, proprietary masonry cleaners available today that are formulated for both general and specific uses, their use is recommended. The manufacturers directions should always be followed to the letter to obtain a satisfactory job. An experienced operator who knows and understands his equipment should only do pressure washing, the cleaning solutions used, the masonry to be cleaned, and be aware of any possible side effects. He should know the proper pressure to use, either water or a cleaning solution, and the effect on the masonry to be cleaned. Colored mortar should be cleaned with extreme caution when any thing other than water is used for the cleaning solution as the final color of the mortar can be changed drastically by using the wrong solution or method. Materials and methods used to clean a masonry wall can have a great effect on the final appearance of the wall.

14

It must be kept in mind that any acid or cleaning solution that attacks the mortar adhered to the

units, can also attack the mortar in the joints ! When some of the paste at the surface of a joint is

removed, the sand in the mortar may be exposed, which will have an effect on the color and

appearance of the joint.

E. MASONRY PROBLEMS Unfortunately, problems do occasionally occur in masonry construction. Sometimes the problem may affect the structural integrity of the building, but usually it is an appearance problem. Some of the common problems are:

1. Wall Cracking a. Poor soil support for foundations. b. Soil heaving or soil subsiding. c. Failure to design foundation for soil characteristics or properties. d. Poor foundation design. (strength, width, depth, etc.) e. Use of masonry units with high shrinkage properties. f. Laying of very wet units with high shrinkage properties. g. Use of units with high expansion properties. h. Lack of contraction, expansion, or, control joints. i. Improperly placed joints. j. Improperly constructed joints. k. Thermal expansion. l. Thermal differential movement between inner structure and outer masonry when tied tightly together. m. Movement of structural frame tied to outer masonry. n. Improper design for wind loads experienced. Wall cracking can be eliminated by proper design, use of proper materials meeting applicable ASTM Standards or Specifications, and the use of proper workmanship in construction.

2. Efflorescence This is probably one of the most common masonry problems, especially in residential and light

commercial construction. The prevention of efflorescence is very simple, DO NOT ALLOW WATER

TO ENTER THE WALL, and, DO NOT USE MATERIALS THAT HAVE A HISTORY OF

EFFLORESCING ! British Standard BS - 3931, defines various classes of efflorescence as: Serious: When a heavy deposit covers at least 50% of the exposed face along with surface powdering or flaking, or both. Heavy: When a heavy deposit covers at least 50% of the exposed face. Moderate: When the exposed face is 10 to 50% covered with a heavy deposit. Slight: When a thin deposit covers less then 10% of the exposed face. Nil: When no noticeable deposit is seen on the exposed face. For efflorescence to occur, there must be soluble salts present in the masonry, and, water must be present in the masonry. These soluble salts may be in the masonry units, mortar materials, from polluted rainwater, or, absorbed from ground water into the masonry wall. Some of the soluble salts that may be present are: sulfates of sodium; magnesium; aluminum; calcium; chromium chlorides; nitrates and salts. Any water-soluble salt present in the masonry could lead to efflorescence problems, if water gains entry into the wall.

15

The water necessary to bring these salts to the surface can come from the water in the mortar; Rain water in an unprotected (uncovered) wall or assembly under construction; lack of, or, poorly designed or constructed flashings; poor joint sealing; porous or highly absorbent masonry units; or, moisture from the interior of the building. Lack of flashing, poorly designed, or poorly constructed flashing, improper air space, air space filled with mortar, mortar bridging the air space, lack of or poorly placed weepholes, weepholes plugged with mortar, etc., can all contribute to improper drainage of water that is in a wall. When water passes through a wall toward the exterior face of the masonry, the soluble salts are picked up and carried along. When the water reaches the exterior face of the masonry, the water eventually evaporates, leaving the salts deposited on the surface. The ambient weather conditions at the time of the water and salts reaching the surface have an effect on the amount of salts deposited on the surface. When the temperature is low, the relative humidity is high, and the wind velocity is low, the evaporation rate is low as is the migration rate of the water through the masonry. When these conditions are present, the depositing of salts is generally high. When the ambient temperatures are moderate to high, with low relative humidities and moderate wind velocities, the evaporation rate is high, and the water may deposit the salts before they reach the surface, and, no efflorescence is noted. Some of these salts, when deposited just beneath the surface of the masonry unit, may cause surface flaking or spalling, or, disintegration of the unit. While it is relatively easy (and expensive) to determine the kind of efflorescing salt by X-Ray diffraction, it may be difficult to determine the source of the salt. There is one form of efflorescence, which can be attributed to the portland cement in the mortar, either in portland cement/lime or masonry cement mortar. It is typically called either "new building bloom" or, "new construction bloom", and can appear on new concrete work as well as new masonry work. It is usually found during cool or cold weather, and is brought about by the release of calcium hydroxide, which is an inevitable product of the hydration process of portland cement. When the weather is cool or cold, the hydration rate of portland cement is slowed down. Then, any water present will carry this product to the surface of the masonry where it is deposited when the water evaporates. This deposit is easily removed by dry brushing or wet washing, and, will typically go away when weather conditions permit further hydration of the cement. This problem normally does not occur in warm or hot weather as the hydration rate of the cement is faster and the calcium hydroxide is bound up by the other products of hydration. This is normally a temporary situation, which while unsightly, is not harmful. There are reported cases where individual masonry materials will not produce efflorescence when tested alone, but, in combination may produce efflorescence. It has been reported that some clay brick containing sulfate, which pass the ASTM efflorescence test, may react with a very low alkali cement in the mortar to produce a water soluble alkali sulfate salt and have heavy efflorescence. Finding the material, or materials, that cause efflorescence can be very complicated. The best prevention is to use materials with a proven record, use proper design methods for the structure, and, insure that good workmanship practices are followed. It should be noted that a Task Group in ASTM Committee C 15,"Manufactured Masonry Units", has been working on various methods of test for determining the efflorescence potential of masonry materials and assemblages for several years. And, a new Guide for the Prevention of Efflorescence may be forthcoming before too long. It has also been found some foreign countries have a different method of testing clay masonry units for efflorescence. Russia's test method places the brick with the bedding face in the water as opposed to the ASTM method which has the brick standing up on end in the water. There is reported cases where a brick had no efflorescence when tested as per ASTM, but had efflorescence when tested by the Russian method.

16

3. Color Variations in Mortar Joints *** The age and consistency, or stiffness, of the mortar at the time the joints are tooled, has a dramatic effect on the final color of the mortar joints. This is true of both regular and colored mortar joints. The longer the time lapse between laying the units, under equal weather conditions, the darker the joints will be. Sometimes a 10-minute difference in tooling time produces strikingly different shades of mortar colors. The wetter the joint is when tooled, the easier it for the wet paste to be brought to the surface. The stiffer the mortar is when tooled, the more difficult it is to produce a smooth, tight joint. When the jointing tool is overused, "burning" of the mortar takes place, and a very dark, almost black joint can be produced. Since weather conditions, mortar wetness or consistency, and, absorption properties of the units all affect the stiffening of the mortar, a set time for proper tooling can not be set. All joints in a given wall or structure should be tooled when the mortar reaches a certain degree of stiffness. A sample panel, or, panels are usually constructed prior to the start of the masonry construction of many commercial buildings. The joint appearance should be looked at, and a decision made at that time on what is desired for that job. Frequently, the sample panels receive tooling relatively early due to the small size of the panel, and the reluctance of the mason to stand around waiting for the proper time, and consequently may not be tooled at the same degree of stiffness as the mortar in the building. When this happens, the mortar joints in the structure do not match those in the sample panel, and then the accusations as to the cause may begin to spread. This is especially critical when a colored mortar is being used, and the desired color was selected based on the sample panel. Color variations within a given length of bed joint may vary from light to dark within several inches or a few feet. Usually this can be attributed to highly different IRA's of the units being used. With units of very low IRA's, the mortar may remain plastic for a considerable length of time, while the mortar adjacent to units with high IRA's may stiffen quite rapidly. Then, when the mason gets ready to tool the joints, he has a mixture of very plastic and very stiff mortar very close together in the same bed joint. While it is recommended that units with high IRA's be prewet prior to use, it can be difficult to get an even saturation of all units in this situation, and may be impractical. Units with a very low IRA are sometimes called "floaters" because they pull little if any water from the mortar, and may "float" on the mortar bed, slowing down the rate of bricklaying considerably. The problem of units with a high degree of variation in their IRA's is relatively easy to detect, but the cure may be difficult to come by.

4. Color Variations in Walls or Sections of A Wall Once a job is started, the same materials should be used throughout the job on the exposed masonry. A change in the cement or sand can dramatically affect the color of the mortar. Masonry units should come from the same lot or production run. Masonry units supplied to the wall should be pulled from several cubes of units at the same time. The mortar should be mixed in the same proportions and to the same consistency for each batch. On jobs that continue through different seasons, or several weather changes such as spring and fall, can have an effect on the mortar color due to varying amounts of retempering done to the mortar. If excessive retempering was done to mortar in one portion of a wall, then that mortar is likely to be lighter in color than the rest of the mortar. Weather conditions at the time of construction can have a temporary effect on the color of the mortar in the wall. If portions of a wall were left unprotected during a rainy spell the wall may be saturated, but upon arrival of warm dry weather, the color may even out and be satisfactory. The materials and methods used to clean a wall can affect the final color of the wall, or, portions of it. If the cleaning work was done in a haphazard manner, maybe using uneven dilutions of a cleaning solution, can have a temporary or permanent effect on the final mortar color. Anything that is not done in

17

a consistent manner can affect the color of the mortar. Uneven exposure of the sand in the mortar joints can have a serious effect on the final appearance and color of the joints. One critical point regarding high pressure cleaning of masonry. Typically, the masonry cleaning is done by an independent masonry cleaning contractor who may or may not have any experience with masonry other than filling the cleaning solution tank, turning on the pump, and, aiming the nozzle. All clumps and splatters of mortar should be manually cleaned from the walls before any other cleaning steps are taken. In many cases, they expect the high pressure to clean everything. If there is enough pressure to clean the mortar clinging to the units, there is enough pressure to seriously damage the mortar in the joints. It is not uncommon to have the high pressure "blow" the mortar out of the joints, especially at the corners. High pressure cleaning can do a great job of cleaning masonry, but it needs to be done properly with the proper cleaning solutions.

5. Leaking and/or Wet Walls Walls that leak noticeably or appear wet long after a rain has stopped can be caused by several factors, either acting singly, or in combinations.

a. Poor Building Design 1. Poor design for roof to wall sealing 2. Poor roof design 3. Lack of flashing 4. Poor flashing detailing 5. Lack of vapor barrier 6. Improper design for expansion or contraction joints 7. Wrong choice of joint type for weather exposure encountered 8. Failure to include weepholes in design

b. Poor Construction Practices 1. Poorly proportioned or weak mortar used 2. Failure to fill all head joints 3. Failure to provide full bed joints - deep furrowing 4. Moving units after placing on mortar bed that has stiffened 5. Using mortar that is too stiff for the job at hand 6. Improper tooling of joints 7. Incorrect installation of vapor barrier 8. Incorrect installation of flashing 9. Improper sealing of roof to wall connection 10. Incorrect installation of expansion or contraction joints or joint material 11. Failure to keep air space open and clean. 12. Allowing mortar to bridge the air space. 13. Failure to place weepholes 14. Weepholes plugged with mortar droppings 15. Incorrect placement of ties, anchors, or reinforcement. When a vapor barrier is specified and properly placed, the water in the humid air inside the building cannot get into the wall and cause problems.

18

When the proper air space is specified, and kept free of mortar bridging the space, any water in the cavity will run down the back of the exterior wythe of masonry until it comes to the flashing which will direct the water to the weepholes where it will exit the wall harmlessly. Any improper or improperly placed ties, anchors, reinforcement, mortar bridging can allow the water to reach the interior wythe and possibly enter the building interior, and, possibly cause damage to the sheathing, insulation, interior walls, floor,and electrical system.

F. ASTM C 780 ASTM C 780,"Standard Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry", covers the test methods to be used in evaluating various mortar properties prior to, and during, construction of masonry structures. Ideally, a mortar to be used on a job would be tested in the laboratory as per C 270, then tested as per the methods outlined in C 780 to test

for field mortar properties. C 780 plainly states in Section 1.3," the test results obtained under this

test method are not required to meet the minimum compressive values in accordance with the

property specifications in Specification C 270". C 780 is strictly a series of test methods that may be used for field testing of actual field proportioned and mixed mortar. It gives the prescribed test methods and gives the prescribed equipment to be used for this testing. This is one of the least understood and most misused of any ASTM Specification and Standard relating to masonry mortar, and, mortar testing !!! Section 1, Scope, of C 780 states:

1. Scope 1.1 This test method covers procedures for the sampling and testing of mortars for composition and for their plastic and hardened properties, either before or during their actual use in construction. 1.2 Preconstruction evaluation of mortars permits a comparison of mortar systems and an approximation, by more complete identification, of the mortar mixture which will be produced at the construction project. The preconstruction laboratory investigation permits the establishment of the compatibility of the individual materials in the mortar and the general strength characteristics of the mixture. 1.3 Construction-site testing procedures permit the establishment of conformance to the proportion specifications and quality control of mortar production. Mix-composition measurements permit the rapid assessment of conformance with the proportion specification and quality control, whereas later-age strength testing provides verification that the mortar ingredients are compatible and are performing normally. The test results obtained under this test method are not required to meet the minimum compressive values in accordance with the property specifications in Specification C 270. In essence, this test method is like the test methods ASTM has for testing concrete, it just gives the test methods to use, it does not have any requirements the test results have to meet. For a specifier to really know what the compressive strength is of a masonry wall, or masonry assemblage, C 270 states it best in Note 7," Where necessary, Testing of a wall or a masonry prism from the wall is generally more desirable than attempting to test individual components". Sometimes, the best compressive strength results which relate to load carrying capacity of a wall may be determined by testing prisms cut from a wall, or preferably, by testing prisms made on the job, by masons working on the job, using mortar used on the job. Prism testing should only be done when the procedures and methods of ASTM E 447," Standard Test Methods for Compressive Strength of Masonry Prisms", are followed. The compressive strength values desired should always be decided upon prior to prism testing, not after a job has started.

19

Any laboratory involved in masonry mortar testing, either by ASTM C 270 or C 780, should have

to demonstrate at least a basic knowledge of both, and have properly trained personnel, the

proper equipment and facilities for testing.

20

ASTM C 144

AGGREGATES for MASONRY MORTAR(Highlights Only)

Referenced Documents:

C 40 Test Method for Organic Impurities in Fine Aggregate

C 87 Test Method for Effect of Organic Impurities in Fine Aggregate on Strength of Mortar

C 88 Test Method for Soundness of Aggregates by Use of Sodium Sulfate or Magnesium SulfateC 117 Test Method for Materials Finer than 75 um (No. 200) sieve in Mineral Aggregates by Washing

C 123 Test Method for Lightweight Pieces in Aggregate

C 128 Test Method for Specific Gravity and Absorption of Fine AggregateC 136 Test Method for Sieve Analysis of Fine and Coarse Aggregate

C 142 Test Method for Clay Lumps and Friable Particles in Aggregates

C 270 Specification for Mortar for Unit MasonryC 404 Specification for Aggregates for Masonry grout

D 75 Practice for Sampling Aggregates

Materials and Manufacture

Aggregate for use in masonry mortar shall consist of natural sand or manufactured sand. Manufactured sand

is the product obtained by crushing stone, gravel, or air-cooled iron blast-furnace slag specially processed toinsure suitable gradation.

Note 1 Care should be taken to ensure a suitable particle shape, since excessive quanities of flat andelongated particles have historically caused problems with workability.

Grading

Aggregates for use in masonry mortar shall be graded within the following limits, depending upon whethernatural sand or manufactured sand is to be used.

PERCENT PASSING

SIEVE SIZE NATURAL SAND MANUFACTURED SAND

4.75 um (No. 4) 100 100

2.36 mm (No. 8) 95 to 100 95 to 100

1.18 mm (No. 16) 70 to 100 70 to 100

600 um (No. 30) 40 to 75 40 to 75

300 um (No. 50) 10 to 35 20 to 40

150 um (No. 100) 2 to 15 10 to 25

75 um (No. 200) 0 to 5 0 to 10

The aggregate shall not have more than 50% retained between any two consecutive sieves of those listedabove nor more than 25% between 300 um (No. 50) and the 150 um (No. 100) sieve.

When an aggregate fails the gradation limits specified in 4.1 and 4.2, it may used provided the

mortar can be prepared to comply with the aggregate ratio, water retention, and compressive

strength requirements of the property specification of Specification C 270.

21

BULKING of SANDS

PERCENT INCREASE in VOLUME OVER DRY RODDED SAND

FINE SAND

MEDIUM SAND

COARSE SAND

Percent increase in volume

over dry, rodded sand

Percent of moisture added by mass

to dry, rodded sand

% Moisture 0 2.5 5 7.5 10 12.5 15 17.5 20

Fine 0 30 37.5 36 32 27 22 16 10.5

Medium 0 20 28 27 23 18 12 6 1.5

Coarse 0 14 17.5 15.5 12 7.5 3 0

BULKINGOFSANDS.XLS

0

5

10

15

20

25

30

35

40

0 2.5 5 7.5 10 12.5 15 17.5 20

% Moisture

%

B

U

L

K

I

N

G

Fine

Medium

Coarse

22

Agency ASTM ASTM UBC ASTM ASTM UBC ASTM ASTM UBC

Spec. C 91 C 1329 24-19 C 91 C 1329 24-19 C 91 C 1329 24-19

Type N N N S S S M M M

Fineness,-325% 24 24 24 24 24 24 24 24 24

Autoclave Exp. Max.% 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Set-Minimum-min. 120 120 120 90 90 90 90 90 90

Set-Max.-min. 1440 1440 1440 1440 1440 1440 1440 1440 1440

psi-min, 7-day 500 500 500 1300 1300 1300 1800 1800 1800

psi-min, 28-day 900 900 900 2100 2100 2100 2900 2900 2900

Air-Min% 8 8 8 8 8 8 8 8 8

Air-Max% 21 16 16 19 14 14 19 14 14

Water Ret.-Min.% 70 70 70 70 70 70 70 70 70

Flexural psi-min. NA 70 71 NA 100 104 NA 115 116

UBC TABLE NO. 24-19-B

RESTRICTED MATERIALS - MORTAR CEMENT

MATERIAL

Chloride Salts

Caboxylic Acids

Sugars

Glycols

Lignin & Derivities

Stearates

Fly Ash

Clay (except Fireclay)

Neither ASTM C 91, , nor ASTM C 1329, have restricted or prohibited materials limits.

Fireclays

NOT PERMITTED IN MORTAR CEMENT

Epoxy resins & derivities

Phenols

Asbestos Fiber

No Limit

5.00%

UBC TABLE 21-19-C

DELETERIOUS MATERIALS

1.00%

0.50%

0.50%

MAX. LIMIT-%

ASTM C 91 Masonry Cement, ASTM C 1329 Mortar Cement, UBC 24-19 Mortar Cement

0.06%

0.25%

1.00%

The test results required above, are based on mortar batched, mixed, and tested in

accordance with the applicable ASTM or UBC specification.

The flexural bond strengths are determined by the method outlined in ASTM C 1072,

Standard Test Method of Masonry Flexural Bond Strength.

The basic difference between ASTM Masonry Cements and the ASTM and UBC Mortar

Cements is the Mortar Cements have a lower Maximum Air Content, and Minimum

Flexural Bond Strength requirements.

23

Note: Two air-entraining materials shall not be combined in mortar.

Hydrated

Portland Lime

or or Aggregate Ratio

Blended Lime (Measured in Damp, Loose

Mortar Type Cement M S N M S N Putty Conditions)

M 1 **** **** **** **** **** **** 1/4

Cement- S 1 **** **** **** **** **** **** 1/2

Lime N 1 **** **** **** **** **** **** over 1/2 to 1 1/4

O 1 **** **** **** **** **** **** over 1 1/4 to 2 1/2

M 1 **** **** 1 **** **** **** ****

M **** 1 **** **** **** **** **** ****

Mortar S 1/2 **** **** 1 **** **** **** **** Not less than 2 1/4 and not

Cement- S **** **** 1 **** **** **** **** **** more than 3 times the sum

N **** **** **** 1 **** **** **** **** of the separate volumes of

O **** **** **** 1 **** **** **** **** cementitious materials

M **** 1 **** **** **** **** 1 ****

M **** **** **** **** 1 **** **** ****

Masonry S 1/2 **** **** **** **** **** 1 ****

Cement- S **** **** **** **** **** 1 **** ****

N **** **** **** **** **** **** 1 ****

O **** **** **** **** **** **** 1 ****

Mortar Type

M

Cement- S

Lime N

O

M

Mortar S

Cement N

O

M

Masonry S

Cement N

OA Laboratory prepared mortar only.C When structural reinforcement is incorporated in cement-lime or mortar cement mortar, the maximum

air content shall be 12%.D When structural reinforcement is incorporated in masonry cement mortar, the maximum

air content shall be 18%.

Mortar Cement Masonry Cement

ASTM C 270, STANDARD SPECIFICATION for MORTAR for UNIT MASONRY

TABLE 1 PROPORTION SPECIFICATION REQUIREMENTS

2500 (17.2)

1800 (12.4)

750 (5.2)

350 (2.4)

2500 (17.2)

1800 (12.4)

750 (5.2)

350 (2.4)

2500 (17.2)

1800 (12.4)

750 (5.2)

350 (2.4)

Min, psi (MPa)

Strength at 28-days,

Average Compressive Water

Retention,

min. %

75

75

75

75

75

75

75

75

75

75

75

75

12

12

14c

14c

20D

12

12

14c

14c

Not less than 2 1/4 and not

18

18

20D

TABLE 2 PROPERTY SPECIFICATION REQUIREMENTSA

more than 3 1/2 times the sum

of the separate volumes of

cementitious materials

Aggregate Ratio

(Measured in Damp, Loose

Conditions)

Air

Content,

Max %

24

SOME REFERENCE MATERIAL

1. ASTM C 144 Standard Specification for Aggregate for Masonry Mortar 2. ASTM C 270 Standard Specification for Mortar for Unit Masonry 3. ASTM C 91 Standard Specification for Masonry Cement 4. ASTM C 1329 Standard Specification for Mortar Cement 5. UBC 24-19 Mortar Cement 6. ASTM C 150 Standard Specification for Portland Cement 7. ASTM C 595 Standard Specification for Blended Hydraulic Cements 8. ASTM C 207 Standard Specification for Hydrated Lime for Masonry Purposes 9. ASTM C 67 Standard test Method for Sampling and Testing Brick and Structural Clay Tile 10. ACI 530 Building Code requirements for masonry Structures & Specifications for Masonry

Structures, also includes Commentaries for both 11. ASTM C 447 Standard test Method for Compressive Strength of Masonry Prisms

The above Standards, Specifications, Codes, Etc,., are subject to change on an annual basis.

25

Sources of Information for The SHORT MASONRY GUIDE 1. American Concrete Institute Manual of Concrete Practice, Part 5 Masonry Structures Code Masonry Structures Building Code Masonry Structures Building Code Commentary Masonry Construction Specifications 2. ASTM (American Society for Testing and Materials) ASTM Book of Standards Volume 04.05, Construction STP 871, Masonry, Research, Application, and Problems Brick Masonry Wall Nonperformance Causes Durability of Brick Masonry: A Review of the Literature, Clayford T. Grimm 3. Brick Industry Association (BIA) Technical Notes on Brick Construction, #23, December 1969, Efflorescence, Causes Technical Notes on Brick Construction, #18, April 1963 Technical Notes on Brick Construction, #7b, January 1965 4. Portland Cement Association (PCA) Concrete Masonry Handbook 5. Many books, journals, magazines, articles, papers, training courses, seminars, and, conversations

with recognizes experts in the field of masonry. Experts: Occupation Dr. H. C. Fischer Consultant, Retired LCCO. Albert Isberner Consultant (retired); PCA-Retired Jake Ribar Consultant, Retired CTL, PCA Tom Grimm Consultant, Retired U of Texas, Austin John Melander Masonry Specialist, PCA Ed Hedstrom WJE, Retired-Lab Mgr.-NCMA, Retired Pat Howley Master Mason, Consultant, Retired ESSROC Cement Val Dubovoy Engineer, CTL(Construction technology Laboratories)Bob Nelson Robert L. Nelson Inc. (Masonry Testing & Investigations) Many Coworkers And, many others too numerous to mention.