UPGRADING OF LATERITIC SOIL WITH PULVERIZED PORCELAIN TILES FOR HIGHWAY CONSTRUCTION

Abstract

The geotechnical properties lateritic soil sample was upgraded with pulverized porcelaintiles (PPT). Lateritic soil sample was obtained and its index, specific gravity and compaction property was determined along with its California Bearing Ratio (CBR). Soil sample was obtained from Shagamu Interchange, Off Lagos-Ibadan expressway, South-West Nigeria while the pulverized porcelain tiles used were obtained from a construction site as waste. The soil samples were mixed with pulverized porcelain tiles in percentage by weight from 0 to 30% at an additional rate of 5%. The index properties of the natural soil showed the soil is silty clayey that belongs to group A-7-6 which is a poor soil according to AASHTO soil classification system. The soil naturally has a specific gravity of 2.65 with 37% of it particles passing 0.075mm, its LL, PL and PI are 46, 16, and 30% respectively, this depicts that the soil was a silty clayey high plastic soil (CH). The lateritic soil was altered by its compaction characteristics upon the addition of PPT which increased the liquid limit but gradually reduces the maximum dry density of the soil. The analyses of test results, it was found that Liquid Limit, Plastic Limit, Plasticity Index, and Optimum Moisture Content decreased consistently with the incremental addition of PPT up to 30%, whereas the Maximum Dry Density decreases with an increase in the optimum moisture content while the California Bearing Ratio (Soaked and Un-soaked) increased with PPT additive. Liquid Limit decreased from 46.7% (unmixed laterite) to 44.6% (30% PPT addition). The Plastic Limit decreased from 16% (natural state of laterite) to 15.6% (when mixed with 30% PPT) leaving the plasticity index reduced to 29% from 30.7%. The percentage of un-soaked CBR increased from 28% at 5% of PPT to 37.1%, while that of soaked CBR increased from 23% (unmixed soil) to 32.6% at 30% of PPT. Also, the free swelling potential of the clayey soil decreases as the percentage of PPT increases. The study asserts that 30% of PPT should be used to improve the geotechnical properties of a lateritic soil for highway construction.