Effect of rice husk ash on plasticity and compaction parameters of a soil-lime mixture

This paper addresses the evaluation of the potential use of ash from rice peel as pozzolanic material acting together with hydrated lime in the chemical stabilization of a residual soil from the Ilha Solteira region, Sao Paulo State, Brazil. Ash contents of 5% and 10% were added to a soil previously stabilized with 8% of hydrated lime, all contents related to soil dry weight, in order to evaluate soil and mixtures performances regarding geotechnical indexes (grain size distribution, liquid limit (LL) and plastic limit (PL)), optimum compaction parameters (optimum water content (w(ot)) and specific apparent maximum dry mass (rho(dmax))) determined at the standard proctor compaction effort, as well as classification of the soils and its admixtures following the MCT Methodology. Data from the testing program lead to the conclusion that addition of ash generated: (i) increases in the parameters LL, PL and w(ot), as well as reductions in the parameters plasticity index (PI) and rho(dmax) of the soil and its admixtures; (ii) the soil and its admixtures were classified as lateritic sandy soils (LA') following the MCT Methodology.