A thesis submitted in pa1iial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 2001

In 1987 Chai Jaturapitakkul investigated the mechanical properties of straw-clay composite and used that material to construct low-cost silo for storage of paddy. The tested results shown that the straw-clay composite is good insulating material and the thermal conductivity of that material is lower than concrete by approximately 20 times. However, the settlement of straw-clay composite was found to be very high as compared another materials. In this research, the settlement and strength was improved by using vetiver grass to replace straw in clay matrix which is used to construct grain silo or low-cost pa1iition walls. Vetiver grass was tested for its moisture content, water absorption and tensile strength. Clay was tested for its water content, specific gravity, Atterberg limits and particle size analysis. The vetiver grassclay composite was tested for its tensile strength, axial compressive strength, flexural strength, shearing strength, bearing strength and density. Six wall panels were constrncted to investigate the settlement and bearing strength by using the vetiver grass-clay composite. Thickness of wall panels were varied 15, 20 and 25 cm. Besides, the wall panels were constructed by different laying patterns namely " straight laying pattern " and " combination of diagonal and straight laying pattern ". The settlement, cumulative water loss, temperature and relative humidity were recorded for a period of 20 days before they were moved to laboratory for bearing tests. According to the testing result, it is evident that the settlement of vetiver grass-clay composite was lower than the straw-clay composite. The bearing strength of straight laying pattern was lower than combination of diagonal and straight laying pattern.