A THESIS SUBMITTED TO THE FACULTY OF CIVIL ENGINEERING, SCHOOL OF GRADUATE STUDIES, ARBA MINCH UNIVERSITYIN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN CIVIL ENGINEERING (GEOTECHNIQUES

Abstract

Due to its versatility and widespread availability, soil has been one of the most widely used building materials for centuries throughout the world. The purpose of this research is to study the suitability of white soil in Laka Kebeles, Dorze Town, Gamo Zone, and Southern Ethiopia for cement stabilized soil block. Due to the high cementing and low shrinkage properties of the soil, the people in this area use this soil as backfill and finishing material. Therefore, this study was intended to investigate the soil for a sustainable and low-cost CSSB technique. A sample of soil was taken from Laka Kebele for both soil suitability tests and trial production of CSSBs. To understand the basic characteristics of the soil, tests such as index property, compaction characteristics, and soil mineralogy were conducted. The index properties of the soil tested revealed that the soil is well-graded, comprising both cohesive and cohesion less soil fractions. Based on this result, the soil in the study area was characterized as sandy clay (SC) and sandy silt (SM) as per USCS and A-2-4 and A2-6 as per AASHTO classification, which is considered good quality material. The mineralogy analysis shows that the presence of Quartz and Kaolinit in the clay portion was found to be responsible for the binding process in the presence of cement. Blocks were produced with two different soils (SC & SM) soil at cement content of 0,2,4,6,8,10,12% by weight of soil. The blocks were also cured for a period of 7,14,28 days and tested for strength and durability. Further tests on the compressive strength and moisture absorption capacity of blocks produced from this soil revealed that the compressive strength of the block increases reasonably well up to 8% of cement. After that, the compressive strength value shows a little bit of increment, up to 12% of cement. This makes the study come up with an optimum cement content (OCC) of 8% for the safe and economic production of CSSB. The water absorption capacity of the block at this OCC is also well below the maximum recommended value.