ABSTRACT

This work seeks to find a way in which lateritic soil within Ota, Ogun State of Nigeria could
be use in the production of hollow sandcrete blocks. This replacement is intended to
observe the effect of lateritic soil on the strength characteristic when employed in the
production of sandcrete blocks. It was deduced from past works that the inclusion of lateritic soil in sandcrete block production will produce a lesser quality blocks but this work seeks to find the maximum permissible replacement that will still make the blocks be within the recommended standard. Sandcrete blocks were produced with each lateritic soil samples from different sources replacing the conventional fine aggregate, sand, in steps of ten percent (10%) to sixty percent (60%) and their compressive strengths determined and compared with that of a
standard sandcrete block to check for the acceptable percentage replacement.
Tests like gradation tests which include sieve analysis and hydrometer test, compaction
test to determine the bulk density, Atterberg’s limit test, specific gravity test were performed on the lateritic soil samples to characterise the soils. The blocks were cured by sprinkling them with water twice daily till the twenty seventh (27th) day. In the compressive strength test, seventy two (72) numbers of 225 x 225 x 450mm hollow laterised sandcrete block sizes were produced and crushed with the compressive strength machine to determine their twenty eight-day compressive strength. Classifying the lateritic soil samples with the Unified Soil Classification System (USCS), it was found out that the lateritic soil is sandy silt of high plasticity and can replace sand by twenty percent (20%). This percentage replacement can be recommended to the block molding industries within Ota.

TABLE OF CONTENT
Content                                  Page
Title page - - - - - - - -   i   
Certification - - - - - - -   ii
Dedication - - - - - - -   iii
Acknowledgement - - - - - - -   iv
Table of content - - - - - - -   v
List of Tables - - - - - - - - x
List of figures - - - - - - - -   xi
Abstract - - - - - - - -   xii
 
CHAPTER ONE
11 Introduction - - - - - -   1
12 Aims and Objectives - - - - - -   2
13 Research Methodology - - - - -   -   3
131 Block Production - - - -   -   4
1311 Materials - - - - - -   4
  1312 Batching and Mixing - - - -     4
  1313 Moulding of the sandcrete block - -    6
14 Curing - - - - - -     7
15 Study Justification - - - - -     7

CHAPTER TWO  
20 Literature Review - - - - -     8
21 Previous works on laterised blocks - - -     8
22 BLOCKS AND BLOCKWORK - - - -      9
  221 Sandcrete Blocks - - - -     9
    2211 Material and Dimension - -     9
    2212 Pre-Cast Sandcrete Blocks - - - -     10
    2213 Mix Proportions - - - - -     10
    2214 Strength Requirements - - - -     10
    2215 Moulding and Compaction - - -     10
    2216 Production/Processing - - - -     10
    2217 Curing - - - - - - - -     11
23 Properties of Block - - - - - - - -     11
  231 Strength - - - - - - - - -     11
  232 Thermal Insulation - - - - - - -     11
  233 Acoustic Property - - - - - - -     11
  234 Fire Resistance and Durability - - - -     12
  235 Water Absorption and Effect of Admixture of Sand -      12
24 Introduction to lateritic soil
25 Review of Nomenclature on Lateritic Soils - -     13
26 Genesis and Evolution of Laterites/ Lateritic Soils -     16
  261 Physical Weathering of Rocks - -     17
  262 Chemical Weathering of Primary Minerals -     17
  263 Accumulation of Sesquioxides in Laterite/Lateritic Soils     18
  264 Evolution of Lateritic Soils - - - -     20
 27 The Structural Development of Laterite Soils - - -     22
 271 Morphological Change - - -     22
 272 Chemical and Mineralogical changes - -       22
            273 Leaching of Dissolved Substances - -   -     24   
  274 Sesquioxide Coatings of Fine Particles - -     25
  275 Formation of the Concretionary Structure -     26
  276 Dehydration of Sequioxides and Secondary Minerals    27
247  Sesquioxides in the Induration of Laterite Materials     28 
280  LOCATION OF LATERITIC SOILS - - -     28 
281 Parents Materials - - - -     29
282 Climate - - - - -     30
283 Vegetation - - - -   -     31
284 Topography and Drainage Conditions - -     32
285 Geological Time Factor - - -     33
29 MORPHOLOGY AND COMPOSITION OF LATERITE SOILS -     34
  291 Characteristics of Lateritic Soil Profile - -     34
    2911 Soil Layer Overlying Lateritic Bed - -     34
    2912 Lateritic Horizon - - -     35
    2913 Soil Layers below Lateritic Horizon - -     35
  292 Morphological characteristics - - -     35
    2921 Genetic-textural characteristics - -     38
    2922 Colour - - - -     38
    2923 Macro-structure - - -     38
    2924 Origin and state at excavation - -     39
2925 Relation to parent rock - - -     39
  293 Chemical characteristics - - -     39
  294 Mineralogical Characteristics - - -     40
210 Soil Classification System - - - - - -     43
  2101 Unified Soil Classification System (USCS) - -     43
  2102 Soil Classification Tools - - -     44
  2103 Properties of a Well Graded Soil - - -     46
 
CHAPTER THREE  
30 MATERIALS, SPECIMENS, PREPARATION AND EXPERIMENTAL DETAILS
31  Block Moulding - - - - -     48
32 Preparation of disturbed samples for testing - -     48
33 Determination of Moisture Content (Oven Drying Method) -     48
34 Atterbergs Limits Test - - - -   -     48   
35 Grains-Size Analysis - - - - -     48
36   Specific Gravity Test - - - - -     48
37   Soil Compaction Test - - - - - - - -     48
38   Compressive Strength Test - - - - - - -     49
 
CHAPTER FOUR
40 PRESENTATION AND DISCUSSION OF RESULTS - -     50
41 Block Moulding Observations - - - -     50
42 Atterberg Limits’ Test Result - - - -     50
421 Liquid limits test results - - - -   50
  422 Plastic Limit Test Results - - - -   51
43 Grain Size Analysis Result (Gradation) - - -   52
  431 Sieve Analysis Test Results - - - -   52
  432 Hydrometer Test Results - - - -   53
44 SPECIFIC GRAVITY TEST RESULT - - - -   55
45 Bulk/Dry Density Test Result - - - -   55
46 Compressive Strength Test Results - - - -   59
 
CHAPTER FIVE
50 CONCLUSIONS, LIMITATIONS AND RECOMMENDATION - -   61
51  Conclusion - - - - - - - - - - -   61
52  Limitations - - - - - - - - - - -   62
53   Recommendations for further studies - - - - - -   62
 
BIBLIOGRAPHY - - - - - - - - - - - - 63
APPENDICES - - - - - -   70


LIST OF TABLES
21 SUMMARY OF THE CHARACTERISTICS OF ALUMINOUS AND FERRUGINOUS LATRITICS SOILS   
2 2 Generalized Morphological Characteristics of Materials from Lateritic Profile 36   
23 The Chemical composition of laterite materials from various parts of the world37
24 Influence of weathering condition on the mineralogy of typical tropical soil - 41
41 Liquid Limit Results - - - - - -     50
42 Plastic Limits Results - - - - - -   51
43 Sieve Analysis Results - - - - - -   52
44 Hydrometer Results - - - - - -   53
45 Coefficient of Curvature/ Uniformity readings - - - -   54
46 Specific Gravity Result - - - - - -   55
47 Soil Compaction Result - - - - - -   56
48: Compressive Strength Results - - - - -   59

LIST OF FIGURES                                                                                                        PAGE
21 Structural Development of Lateritic Soils - - -     16
22 Chemical and mineralogical characteristics of laterite weathering   18
23 Solubility of hydrated hydroxides and silica in relation to PH -     19
24 Cycle of weathering and laterization process - -     21
25 Change in chemical composition at various stages in the  
       formation of aluminous lateritic rock - - -     23
26 X-Ray diffraction patterns of the coarse clay fraction of lateritic soil -   25
27 The influence of Iron oxide content on the
       strength of concretory aggregate - - - -     26
28 Simplified geological map of West Africa - - -     29
29 Weathering Sequence of Basaltic lavas  
          in relation to weathering conditions - - -     30
210 Morphological characteristics of laterite profile
          in relation to vegetation cover - - - -     31
211 Soil and slope relationship in south west Nigeria - -     33
212 A typical lateritic profile - - - -     40
213 Chemical composition of laterite material - - -     41
214 Casagrande’s plasticity chart showing several  
         representative soil types developed from (Casagrande, 1948) -   44
215 Auxiliary Laboratory Identification Procedure - - -   45  
216 Typical grain size distribution curves - - - - - - - 46