Effect of Addition of (Cement- Silica Dust) Mixture on Compaction and Unconfined Compressive Strength of Soil

Abstract

That to deal with soils that have problems such as (swelling, sponge behavior ( Fatigue ), hydraulic consolidation and cracks) in a way reinforced concrete is very expensive, but the treatment of these soils in a way added stabilizers local is acceptable, available, inexpensive, give acceptable strength, improve soil properties such as durability and exposure to environmental conditions and used in most countries of the world. This investigation is conducted to study the effects of the mixture (cement- silica dust) on the bearing and stabilizing soils, study the effect of different times of maturation of the specimens (7, 14, 28) days at constant temperature (26 - 30) oC and study the effect of the conditions of inundation specimens with water on Unconfined compressive strength. (cement- silica dust) Were used by a mixture of them (1:1), Foure levels of addition were used (4%, 8%, 12%,16%) of the weight of dry soil. All specimens were exposed to same curing condition ( curing temperature 26- 30 oC). Different curing times were (7,14,28) days and some of specimens were exposed to inundation conditions. The experimental results illustrate that the maximum dry density (M.D.D) and plastic index (P.I) decrease with the addition of mixture, but the optimum moisture content (O.M.C) is increases with increasing of the mixture content. Unconfined compressive strength increases with increase of curing time but it decreased with and without of the mixture (C-SL) when the specimens exposed to inundation condition for all curing time.