Strength characteristics of compressed stabilized earth block made with Selected regional soil

Abstract

Earth as a construction material has been used for thousands of years by civilizations all over the world. Due to low cost and relative abundance of materials, building with Compressed Stabilized Earth Block (CSEB) is becoming popular now-a-days mainly in less flood-prone areas. Strength-deformation characteristics of CSEB is the main focus of this research. Soil samples were collected from Savar (red clay) and 7 different places of Shariatpur (floodplain) district in Bangladesh. For making CSEB, sand, cement, jute and lime were used as stabilizer with the selected soil. This research work evaluates the effects of sand, cement, jute, and lime on the compressive strength and deformation characteristics of CSEB. In this research work, a total of 57 groups CSEB was prepared. Extensive experimental investigation has been carried out to evaluate the effects of different grain size of sand (coarse sand, fine sand and mixes of fine and coarse sand) with the addition of cement in a certain proportion on the compressive strength of Cement Sand Stabilized Block (CSSB). For making CSSB, 3-9% cement was used with 20-60% coarse sand and in some cases 30-60% mixed sand (mixes of coarse sand and fine sand) by weight. In addition to that, one group of compressed earth block was prepared without any stabilizer so that improvements due to stabilization can be studied as compared to the performance of non-stabilized blocks. A series of blocks having dimension of 240 mm × 115 mm × 90 mm were molded using “Auram Earth Block Press 3000”. After manufacturing, the blocks were cured for 28 days at natural weather condition. Unit weight, moisture content, compressive strength and water absorption capacity test of the CSEBs were conducted after proper curing. The compressive strength (average strength of five blocks) of CSEB was found to be between 0.89 and 6.07 MPa consisting of 3-9% cement, 20-60% coarse sand and 50-60% fine sand by weight. Moisture content and unit weight of CSEBs were varied from 0.2 to 19% and 1.2 to 2.1 gm/cm3, respectively. However, the results obtained from this study may be useful in reducing the consumption of fired brick used as non-load bearing building block in construction sector of Bangladesh.