Effect of Mineralogy on Performance Characteristics of Compressed

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


•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


•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


•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


•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


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


Cement Content %

Com

pre

ssiv

e S

trength

N/m

m2


0 3 5 6.5 81500

1550

1600

1650

1700

1750

1800

1850

1900

1950

2000

Density


Cement Content %

Densit

y

Density typically within the range of 1500 – 2000kg/m3


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

Documents

Effect of Mineralogy on Performance Characteristics of Compressed