Abstract
The reuse recycling materials or industrial waste materials with aims to reduce pollution and environmental pollution, strongly supports concept of green building. Fly Ash is result of combustion pulverized system coal at the PLTU Tenayan, is no longer included in the B3 waste category. The usage of Fly Ash usage as building material, mine restoration, roads in this decade, is to replace cement or lime. The fly ash composition is mixed with lime for sub-base, will applied on high plasticity soils. A fix-mixture of soil and lime 5%, mixed with fly ash up to 30% of the mixture. The samples test was made at Optimum Moisture Content, with density values around Maximum Dry Density i.e. under compacted (under MDD) and over compacted (above MDD). Consolidated testing was performed with and without curing. Changes of load are represented by load increment ratio (LIR). The selected LIR value is 1.0; 1,5; and 2.0. The results showed that the higher of density, the volume of void is lower. The soil compression index value is the same for all density values, if the soil structure has not destroyed. or fatigue yet. In samples with crushed/broken soil structures, the value of the compressibility index decreased sharply. Curing successfully decreased the void ratio and compressibility of the soil. The strength of fly ash will decrease when reacting with water, so if soil burdened, the void ratio decreases drastically. The formation of strong molecular bonds between Fly ash and lime takes time. So, the compressibility value of the sample by curing 28 days is better than without curing. The composition levels between fly ash and lime also affects the compressibility index of the mixture. The optimum combination occurs in samples with a fly ash content of 25%.
