Possible developments of building technology in relation to low cost housing in Pakistan

This study relates the recent developments that have taken place in soil stabilization techniques to low-cost housing in Pakistan. The investigation has been carried out in three distinct phases.The first phase of this study undertakes a brief review of the housebuilding in the country. A survey of the building materials in a selected region helped remove a handicap due to lack of factual informa¬ tion in this sphere. None of the existing building materials, due to their scarcity and high costs, was found to be within the means of the common man. Attention therefore had to be focused on earth which inspite of it3 shortcomings continues to provide shelter to a vast majority of the population in the Indus Plains. A study of earth housing in these plains as well as in some other developing countries helped isolate problems associated with the use of earth as building xaaterial. Rainfall, particularly in conjunction with winds, was found to be one of the important factors responsible for bringing this most abundant of the building materials into disrepute. In recent years an extensive use of soil stabili¬ zation techniques ha3 been made in connection with the highway and airfield construction in other parts of the world. An application of the knowledge and experience gained in this field to revitalize earth housing is found to be the only realistic approach to the housing problem in the Indus Plains.The second phase, which forms the core of this project, deals in classifying and locating the soil3 of the Indus Plains for the purpose of their planned use in stabilized earth housing. All soils encountered in the region are classified into major groups based on their identifiable characteristics significant from a stabilization viewpoint. This objective was achieved through the cooperation of a soil survey agency. i. Soil information thus obtained i3 presented in the form of simple yet comprehensive Soil Maps. These maps provide ready information about all the important aspects of soil for undertaking a stabilized earth project. The problem of identifying the soil, upon which rests the whole success of this technique, is therefore almost completely solved. After the soil has been correctly identified it only remains to determine the requirements in terms of cement, water and compaction for achieving tie desired results.The third phase of this investigation was devised to determine the above requirements for each soil group so as to eliminate the need for elaborate testing on every site. This involved stabilization of repre¬ sentative samples of all major soil groups in the laboratory with varying amounts of Portland cement. The specimens thus prepared were tested for durability. Results obtained from soils stabilized with fairly low cement contents compared favourably with those of burnt brick. Based on these results the quantity of cement, amount of moisture and compactive effort needed for each soil group is recommendedThis study has thus provided answers to all the practical problems of soil stabilization for low cost housing in the form of simple reference maps