Improvement an Expansive Soil using Polymethacrylate Polymer

Abstract

One of the worldwide problematic soil is expansive clay accompanied by large volume change response when it subjected to a change in the water content. A chemical method for enhancing the swelling of expansive clayey soil is provided using Polymethacrylate (PMA) polymer material. An expansive soil is prepared in the laboratory by adding bentonite. Then experimental program is conducted to estimate the effects of adding the (PMA) polymer on the properties of the prepared expansive soil. Modified clay specimens are characterized based on sieve analysis, hydrometer, Atterberg limits, standard compaction, swelling potential, swelling pressure, unconfined compression strength and California Bearing Ratio (CBR) tests and 10 groups of soil samples are prepared at three various percentages of PMA (i.e. 3%, 5% and 7% by weight of dry soil).The tests results indicated that the induced of PMA polymers within expansive soil caused a decrease in the liquid limit (LL), plasticity index (PI), free swell%, rebound index (Cr) and optimum moisture content (OMC) and increase in plastic limit (PL), Unconfined Compression Strength (UCS) taken into consideration the influence of increasing curing time, compression index (Cc) and California Bearing Ratio (CBR). Also adding PMA polymers increase maximum dry density (MDD).The swelling potential decreased up to 71.7% with increasing PMA content to 7% respectively. The results of the tests indicated that the polymers significantly overcome the problems of expansive soils. In addition, higher UCS by 52.8% are observed by adding PMA with a percentages of 7%. Also adding same percentages of PMA polymer caused increasing in CBR value by 72.8%.