ai 108 for+shotcrete+inspector use+of+kim+admixture

7/29/2019 AI 108 for+Shotcrete+Inspector Use+of+KIM+Admixture

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IMPORTANTYou are responsible to ensure that correct procedures are ollowed in all aspects oplacing shotcrete containing KIM admixture. KIM Admixture is used to make awaterproo membrane out o shotcrete. This is dierent rom traditional construction,where the shotcrete just orms the structure. KIM shotcrete will be the only barrierto water penetration. This means that common deects ound in typical shotcretecannot be tolerated. Poor consolidation, unplanned cold joints, cracks, penetrations,contaminations, etc. will all result in a leaking structure. To avoid leakage and to achievesuccess you must ollow the critical instructions outlined in this document.

Follow the guidelines o ACI 506R Guide to Shotcrete.

PREPARATION FOR SHOTCRETINGAll equipment shall be appropriate and suitable or dry-mix or wet-mix shotcrete, asapplicable, in accordance with the requirements o ACI 506.2.Shotcrete orms must be braced to avoid excessive vibration and must be designed toallow or the escape o compressed air and rebound.Inspect reinorcing steel, anchors, mesh and embedments and ensure they are properlyplaced and secured such that they do not vibrate or otherwise move during shotcreteplacement. Ensure that sucient clearances have been provided, and that reinorcingsteel is ree o grease, oil, loose rust and other coatings that may impair bond with theshotcrete.I possible, the clearance around exposed bar should be three times the maximumaggregate particle in the shotcrete mix.I the design allows, lapping o the reinorcing splices should be avoided. Lapped bars

should be spaced apart at least three times the diameter o the largest bar at the splice.Ensure that tie wires are cut to prevent loose ends rom interering with the encapsulationo reinorcement.Ensure that all pipes and other penetrations are in place and prepared according toApplication Instruction 303 - Waterproong Pipe Penetrations.Ensure there are no unintended penetrations through the shotcrete element such asexcess rebar, tie wires, etc. that could provide a migration path or water.Ensure that the Krystol Waterstop System has been applied to all existing concrete/shotcrete suraces (reer to Cold Joints and Construction Joints section below).Ensure that earth, rock, concrete and masonry suraces, as applicable, are preparedin accordance with ACI 506.2. All suraces to be shot must be brought to a saturatedsurace dry (SSD) condition immediately prior to shotcrete application.Ensure that ree standing water is drained away rom shotcrete operations.

Ensure that shotcrete is not placed during rainy or windy weather.

Use of KIM Admixture: Instructions for Shotcrete Inspector

SAFETY

The saety precautions or shotcretecontaining KIM admixture are thesame as or regular shotcrete.

Application InstructionsApplication Instruction 108


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SHOTCRETE SUPPLYInspect the ready mix shotcrete batch ticket to veriy that the correct shotcrete mixturehas been supplied with KIM added at the specied addition rate.Ensure that the shotcrete air content and slump are in the specied range prior todischarge into the shotcrete pump.Slump - Add a mid or high range water reducer (superplasticizer) as necessary to achievethe required slump. Only add water with the approval o the shotcrete suppliers qualitycontrol technician. Record all water additions on the batch ticket and do not exceed thespecied water-cement ratio (max 0.40 or shotcrete).Air Content - Add additional air-entraining admixture as necessary to achieve therequired air content.

SHOTCRETE APPLICATION

Veriy that shotcrete nozzlemen have been prequalied to shoot on the project:- All nozzlemen must be ACI certied in the correct category (wet-mix vertical, wet-mixoverhead, dry-mix vertical or dry-mix overhead).- The nozzlemen should have passed prequalication job-specic mock-up tests.Monitor the shotcrete application to establish that the nozzlemen are using properapplication procedures as recommended in ACI 506R Guide to Shotcrete. In particular:

Ensure the nozzlemen completely encase reinorcing steel by shooting withsucient velocity and plasticity so material fows around and behind thereinorcement.Ensure the ront ace o reinorcement remains clean during encasement, andthat an air lance is used to remove overspray and rebound prior to shotcreteplacement. Rebound must not be salvaged or later use.Ensure sucient shotcrete cover is applied over reinorcement as required

by project specications, and that tie wire ends do not protrude through theshotcrete cover.Shotcrete Joints Unless otherwise specied, ensure that unnished work doesnot stand more than 30 minutes unless cold joints are provided or. I the useo accelerating admixtures causes shotcrete to harden in less than 30 minutes,cold joints must be provided or at shorter time intervals (reer to Cold Joints andConstruction Joints section below).I deects are observed during shooting, get the contractor to stop and cut out thedeects while the shotcrete is still plastic and reshoot the aected area. Deectsinclude:

- Entrapped rebound and overspray- Voids o incomplete consolidation, including shadows behind rebar

- Sloughs, delaminations, plastic shrinkage cracks, etc.


Use of KIM Admixture: Instructions for Shotcrete Inspectorpage 2 of 3


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COLD JOINTS AND CONSTRUCTION JOINTSEnsure the Krystol Waterstop System (consisting o Krystol Waterstop Grout and KrystolWaterstop Treatment) is applied to all preplanned construction joints at the end o ashit using one o the ollowing procedures:

- Application Instruction 203 or shotcrete-to-shotcrete construction joints.- Application Instruction 201 or wall-to-slab construction joints.

Ensure that all pipes and other penetrations are prepared to receive the KrystolWaterstop System as described in Application Instruction 303.Ensure proper surace preparation prior to installing the Krystol Waterstop System orplacing the next layer o shotcrete.

- Plastic Shotcrete Broom or trim by trowel to the specied angle.- Hardened Shotcrete Use a high pressure water blast to remove sheen,overspray, dust, curing agents or other materials detrimental to goodbonding.

Ensure all suraces to receive the Krystol Waterstop System or additional shotcrete are

dampened to a saturated-surace-dry (SSD) condition to ensure adequate bonding.

CURING AND PROTECTIONEnsure that resh shotcrete is protected rom rain, wind, direct sunlight and reezingtemperatures. Prevent premature drying by using ogging/misting equipment or othersuitable protective measures.Ensure that all shotcrete is cured in accordance with ACI 308.1 immediately ater nalnishing.Wet curing or a minimum o 7 days is preerred.I wet curing is not possible, use a curing compound in accordance with ASTM C309.Note that or rough textured shotcrete suraces, curing compounds are oten applied attwice the amount used or cast-in-place concrete to account or the greater surace area.

INSPECTION OF FINISHED WORK:Hardened shotcrete should be sounded with a hammer to locate hollow-sounding areas resultingrom rebound pockets or lack o bond. Such hollow-sounding areas, voids, sags and other deectsshould be careully cut out and replaced ollowing the procedures or cold joints.

REFERENCEApplication Instruction 107 Instructions or Shotcrete Nozzleman and CrewApplication Instruction 201 Krystol waterstop system (Internel Method) - wall to slabApplication Instruction 203 Krystol waterstop system (Shotcrete) - Horizontal and Vertical

Construction JointsApplication Instruction 204 Krystol waterstop system (Shotcrete) - Treatment o Unintended

Cold Joints

CRITICALUnintended cold joints may developalong lit breaks during benchgunning i the previous layer oshotcrete hardens beore the nextlayer is placed. This is commonduring hot weather or when usinghighly accelerated mixes.

Ensure that lit breaks are inspectedas described in Application

Instruction 204, and that a slurrycoat o Krystol Waterstop Treatmentis applied beore the next layeris shot i the previous layer hasalready hardened. This will requirecontinuous inspection o theshotcrete lits during the shootingprocess.


Use of KIM Admixture: Instructions for Shotcrete Inspectorpage 3 of 3


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ai 108 for+shotcrete+inspector use+of+kim+admixture

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