PROPERTY CHARACTERISATION OF CONCRETE WITH GROUND GLASS AS PARTIAL REPLACEMENT FOR CEMENT

Abstract

Suitability of ground glass culet as partial replacement for Portland cement in concrete was investigated. Three grain size ranges or ground glass were considered as partial replacement for cement in concrete. The sizes ≤0.300mm, ≤0.150mm and  ≤0.075mm were used at 0%, 5%, 10%, 15%, 20%, 25% and 30% replacement levels. The effects of these on the properties of fresh and hardened concrete were investigated. The results showed that at fixed water-cement ratio and for every 5% increase in the replacement of ground glass for cement, there was an increase in the initial and final setting times as well as in workability (slump) of the concrete. The compressive strength was found to be inversely proportional to both the particle size of the ground glass and the quantity of ground glass replacement for Cement. However, the three grain size ranges of ground glass were found to be adequate as partial replacement for cement in concrete production. The concrete with ground glass of ≤0.075mm grain size gave the best results that compared favourably well with that of normal concrete at all levels of replacement. Its compressive strengths at 28-day with 5%, 10%, 15%, 20%, 25% and 30% replacement for cement were 25.89, 22.11, 21.51, 19.84. 18.73 and 16.80 N/mm², while at 56-day the strengths were 30.00, 29.73, 29.22, 28.60, 26.16 and 24.73 N/mm² respectively. The coefficients of regression show that the quantity and sizes of ground glass have no serious adverse effects on the compressive strengths. The pozzolanic activity index (PAI) was reducing as the quantity of ground glass replacement for cement was increased but the rate of reduction was lowest at 56-day Curing.