THE EFFECT OF LATEX POLYMER ADDITIVE IN STRENGHT OF CLAY FOLLOWING ONE-DAY CURING TIME

Abstract

Some roadways in Indonesia were constructed over expansive clay. The bearing capacity of this clay is very much influenced by water content. It will weaken in saturated condition but will be stronger in dry condition; it shrinkage shear strength characteristics will be influendef by the water content. Rroadways which were built on this type of clay often failed prematurely, for example: they are prone to crack/or rut before achieving its design life. Stabilization may be done as an alternative to overcome problems associated with the effect of water content to the bearing capacity of this clay. This research was carried out to analyse clay sample obtained from Gading km.33 Wonosari. This clay samples were re-compacted in the laboratory at 95% γd,max following the addition of latex polymer at 2.5, 5, and 10%. After 1 day curing time, the compacted samples were subsequently subjected to the following tests: triaxial unconsolidated undrained (UU), California Bearing Ratio (CBR) and unconfined compression. The tests results showed that the clay samples can be classified in accordance with Unified Classification and AASHTO Classification systems as a CH and A-7-6 respectively. The polymer additive was found to reduce the Liquid Limit (LL) whilst maintaining the Plastic Limit (PL), which resulted in decreased Plasticity Index (PI). The additive also increased the fines fraction of the clay particles. Furthermore, the additive also improved the soaked CBR value and reduce the swelling. This research concluded that latex polymer additive filled and closed the soil’s porosity, made it more impermeable and subsequently increased the saturated soil’s strength without changing any physical characteristics.