effect of mineralogy on performance characteristics of compressed
DESCRIPTION
Laboratory analysisTRANSCRIPT
EFFECT OF MINERALOGY ON PERFORMANCE CHARACTERISTICS OF COMPRESSED STABILIZED EARTH BLOCKS (CSEB)
Emeso B. Ojo MNSE
CSEB Research GroupNIGERIAN BUILDING & ROAD RESEARCH INSTITUTE
PRESENTATION OUTLINE
Introduction Background Objective Scope Research Methodology Results and Discussion Conclusion
INTRODUCTION The provision of adequate housing has continued to
be a daunting task around the world. Exponential growth of population Low gross national product Lack of purchasing power Scarcity and/or high cost of conventional building materials
Providing adequate housing requires continuous research and investment especially in appropriate technologies
Appropriate technologies Use of locally available materials, methods or practices Hence, reduce cost of construction and Cost to the environment Contributes to local economic development
WHAT ARE CSEBS?
Walling material Basically earth + stabiliser that has been
compressed Earth construction - old technology Third of the world’s population has been
reported to live in earth houses
WHY USE CSEBS?
An appropriate technology Locally available materials: lowers
transportation costs Cheaper: ensure availability of affordable
housing for a wider population Creates job opportunities Possess very good insulation and thermal
properties Higher energy efficiency compared to other
building materials
CSEBS….. ISSUES
Poor patronage in Nigeria Earth construction still associated with
poverty in Nigeria GIZ and GEMS2 2013 report
Scarce data on the properties of blocks Difficulty with use Dearth of skills Unavailability of ready blocks Aesthetics of the blocks.
LATERITES
Products of chemical weathering of igneous rocks in hot and humid climates.
Properties of laterites would be greatly influenced by their mineralogical composition which is a function of
he nature of parent material, the age of the land surface, climate, topography and drainage conditions. Because these factors vary from site to site within the country, there is the need to document the characteristics of laterites from different parts of the country in order to produce guidelines for use of laterites from various parts of the country.
OBJECTIVES
The main objective of this study is to investigate the effect of mineralogy on the performance of CSEBsIn order to achieve this, the following objectives have been outlined:
Determination of index/engineering properties of samples collected from various locations
Determination of engineering classification of these soils
Determination of mineralogical composition of soils Determination of strength and durability of CSEBs
SCOPE OF WORK
RESEARCH METHODOLOGY
The study was carried out in three phases: Determination of geotechnical properties of
samples Determination of mineralogical composition
of samples Production and testing of blocks
SAMPLE COLLECTION
•Five identified burrow pits within the F.C.T
GEOTECHNICAL PROPERTIES OF SOILS
Natural moisture content Particle density Atterberg limits Particle size distribution Compaction
GEOTECHNICAL PROPERTIES OF SOILS Natural moisture content Particle density Atterberg limits Particle size distribution Compaction
•An important index•Determines soil behaviour and properties•Used for phase relationships of air, water and solids for a given volume of soil•Was conducted using the oven drying method in accordance with BS 1377: Part 2: 1990
GEOTECHNICAL PROPERTIES OF SOILS Natural moisture content Particle density Atterberg limits Particle size distribution Compaction
•To determine ratio of mass of a unit volume of soil to the mass of the same volume of water•Used for phase relationships of air, water and solids for a given volume of soil•Used for determining grain size distribution using the sedimentation method.•Was conducted using the small pyknometer method in accordance with BS 1377: Part 2: 1990
GEOTECHNICAL PROPERTIES OF SOILS Natural moisture content Particle density Atterberg limits Particle size distribution Compaction
•To determine basic measure of the critical water contents of a fine-grained.• Shrinkage limit• Plastic limit• Liquid limit
•Used for soil classification
•All tests were conducted in accordance with BS 1377: Part 2: 1990
GEOTECHNICAL PROPERTIES OF SOILS Natural moisture content Particle density Atterberg limits Particle size distribution Compaction
•To determine the percentage of different grain sizes within a soil•Sieve analysis determines the distribution of coarser particles.•Sedimentation method is used to determine the distribution of finer particles.•Combined wet sieving produces a continuous psd curve•Used for soil classification•Performed in accordance with BS 1377: Part 2: 1990
GEOTECHNICAL PROPERTIES OF SOILS Natural moisture content Particle density Atterberg limits Particle size distribution Compaction
•Is a process whereby soil particles are packed more closely together, thereby increasing the dry density•The test is performed in order to determine the optimum moisture content at which a particular soil attains its highest dry density•Light compaction was conducted in accordance with BS 1377: Part 2: 1990: 3.4
MINERALOGICAL COMPOSITION OF SOILSX-ray Powder Diffraction method is a technique for identifying the atomic and molecular structure of
crystalline materials (salts, minerals, metals etc) A sample is mounted and gradually rotated while being bombarded with X-
rays, producing a diffraction pattern of regularly spaced spots known as reflections.
By measuring the angles and intensities of these diffracted beams, a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds and various other information
The two-dimensional images taken at different rotations are converted into a three-dimensional model of the density of electrons within the crystal using the mathematical method of fourier transforms
Because the positions of the peaks in a powder pattern are determined by the size, shape, and symmetry of the unit cell and the peak intensities are determined by the arrangement of atoms within the cell, the powder pattern is a characteristic “fingerprint” of a phase.
These experimental powder pattern is searched against the Powder Diffraction database containing the patterns of > 700,000 pure compounds
PRODUCTION OF TEST PIECES
Test pieces were produced as specified in the Compressed Earth Blocks: Manual of Production (Rigassi 1985)
PULVERIZING• M
anual crushing to disintegrate particles held up by clay
SCREENING• 2
0mm sieve
• to remove coarse particles
MEASURING OUT• C
ement, soil and water are measured out as dry weights
MIXING
COMPRESSION Dynamic compaction at a compactive effort of 4N/mm2
TESTING OF PIECES
Drying of test pieces 60˚C over a 48hr period Change in successive
weights > 0.1%
Determination of density using the linear method
Determination of compressive strength
Dry Wet
Determination of water absorption
Total immersion for 24hrs
RESULTS AND DISCUSSION
LOCATION KRD BMB ANA GVL KUJ15.22 15.51 13.05 5.93 12.27
Gravel 4 4 5 14 2
Sand 38 34 51 41 40
Silt 14 28 28 17 28
Clay 34 32 16 28 10
LL 41.2 41.4 28.8 44.2 45.6
PL 29.7 31.2 16.9 32.5 NP
LS 8.05 8.49 7.19 9.07 4.8
PI 11.6 10.6 11.9 11.7 NP
2.46 2.49 2.48 2.61 2.6
1.72 1.72 1.83 1.77 1.69
18.5 18.7 13.8 16.5 17.8
ML ML SC SM SM
MOISTURE CONTENT (%)
PARTICLE SIZE DISTRIBUTION
ATTERBERG LIMITS (%)
SOIL CLASSIFICATION (USCS)OPTIMUM MOISTURE CONTENT (%)
MAXIMUM DRY DENSITY (Mg/m3)
SPECIFC GRAVITY
Geotechnical Properties of Soils
RESULTS AND DISCUSSION
Location Mineral Content Chemical Formula %Anagada Quartz, syn SiO2 48.2
Kaolinite Al2Si2O5 ( OH )4 29.9
Microcline, ordered KAlSi3O8 21.9
Bombo Quartz low, syn O2Si 40.1
Dickite-2M1 Al2Si2O5 ( OH )4 32.7
Kaolinite Al2Si2O5 ( OH )4 27.2
Games Village Quartz SiO2 42
Kaolinite-1Ad Al2Si2O5 ( OH )4 21.8
Attapulgite MgAlSi4O10 ( OH ) ·4H2O 22.4Illite-Montmorillonite K - Al4 ( SiAl )8O20 ( OH )4 ·xH2O 13.8
Kuje Quartz SiO2 44.8Dickite-2M1 Al2Si2O5 ( OH )4 34.3Kaolinite Al2H4O9Si2 20.9
Kurunduma Quartz low, syn O2Si 31.4Greenalite-1T, sy Fe3Si2O5 ( OH )4 20.2Tosudite Na0.3Al6 ( Si , Al )8O20 ( OH )10 ·4H2O 14.9Kaolinite-1A Al2Si2O5 ( OH )4 16Illite-2M1 (NR ( K , H3O ) Al2Si3AlO10 ( OH )2 17.6
Mineralogical Composition of Soils
SUITABILITY OF SOILS
0.00
2000
0000
0000
001
0.02
0000
0000
0000
01
0.20
0000
0000
0000
1
2.00
0000
0000
0001
20.0
0000
0000
0001
0
10
20
30
40
50
60
70
80
90
100
KRD BMB ANA GVL KUJ
Particle size (mm)
Perc
enta
ge p
assin
g %
GravelSandSilt
Recommended gradation•Gravels: 0-40%•Sands: 25-80%•Silts:10-25%•Clays: 8-30%
SUITABILITY OF SOILS
20 25 30 35 40 45 50 550
5
10
15
20
25
30
35
KRD
BMB
ANA
GVL
Liquid Limit %
Pla
stic
ity Index %
ARS 680:1996
PERFORMANCE OF CSEBS
0 1 2 3 4 5 6 7 8 90
1
2
3
4
5
6
7
8
9
Dry Compressive Strength
Games Village Kuje Kurunduma Anagada Bombo
Cement Content %
Com
pre
ssiv
e S
trength
N/m
m2
PERFORMANCE OF CSEBS
0 1 2 3 4 5 6 7 8 90
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Wet Compressive Strength
Games Village Kuje Kurunduma Anagada Bombo
Cement Content %
Com
pre
ssiv
e S
trength
N/m
m2
PERFORMANCE OF CSEBS
0 3 5 6.5 81500
1550
1600
1650
1700
1750
1800
1850
1900
1950
2000
Density
Games Village Kuje Kurunduma Anagada Bombo
Cement Content %
Densit
y
Density typically within the range of 1500 – 2000kg/m3
PERFORMANCE OF CSEBS
2 3 4 5 6 7 8 98
10
12
14
16
18
20
Water AbsorptionGames Village Kuje Kurunduma Anagada Bombo
Cement Content %
Wate
r A
bsorp
tion %
MINERAL COMPOSITION OF SOILS
Anagada
Bombo
Games Village
Kurunduma
Kuje
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
48.2
40.1
42
44.8
31.4
29.9
27.2
21.8
20.9
16
21.9
32.7
34.3
22.4 13.8
20.2 14.9 17.6
Quartz, syn Kaolinite Microcline, orderedDickite-2M1 Attapulgite Illite-MontmorilloniteGreenalite-1T, sy Tosudite Illite-2M1 (NR