UNIVERSITY OF NAIROBI Investigation of the effects of Rice Husk Ash (RHA) on the engineering properties of red coffee soil for sub-grade By Maina R Samuel F16/3541/2008 Project supervisor: Eng J.R Ruigu Examiner: Dr. S.N Osano A project submitted as a partial fulfillment for the requirement for the award of the degree of BACHELOR OF SCIENCE IN CIVIL ENGINEERING APRIL 2014