Characteristics of Cold-Bonded Lightweight Aggregate Produced with Different Mineral Admixtures

Cold bonded lightweight aggregate (LWA) was produced by adding 0%, 25% and 50% granulated blast furnace slag (GGBS) or rice husk ash (RHA) to fly ash (FA) by the pelletization process with cement additives. The results show that GGBS addition significantly improved the crushing strength of LWA, whereas there was no effective on crushing strength of LWA when RHA was used. GGBS addition significantly reduced the water absorption of LWA; on the contrary, effect of RHA was to increase the water absorption. Unit weight of LWA added RHA was in range of 719-903 kg/m3, while that of LWA added GGBS was in range of 918-1082 kg/m3. High performance lightweight concrete (LWC) made with the selected LWA (60% FA + 40% Cement and 30% FA + 40%Cement + 30%RHA) had unit weight lower than 2000 kg/m3. The 28-day compressive strength of the LWC was in range of 49 to 57 MPa. The results of the electrical resistivity and ultrasonic pulse velocity tests indicate that the LWCs might be considered to be durable concrete.