Authors:Olorunnisola, A.O; Pitman, A; Mansfield-William, H
Abstract:This work examines the effect of CaCl2 on the hydration of rattan (Laccosperma secundiflorum) and coconut (Cocos nucifera) husk particles mixed with Portland cement. Hydration tests were conducted in sealed thermally insulated containers using an aggregate/cement/water ratio of 15 g : 200 g : 90.5 ml. CaCl2 was added at four concentrations (by weight of cement): 0 (control) 1, 2 and 3% for the rattan and coconut husk particles, and at 0 (control) and 3% for a 50 : 50 mixture (by weight) of rattan and coconut husk. Hydration temperature was monitored on-line over a period of 23 h. The compatibility of both aggregates and their 50 : 50 mixture with Portland cement was assessed using the parameters of time to maximum hydration temperature, maximum hydration temperature, inhibitory index, and rate of heat generation. Findings showed that without CaCl2 both aggregates exhibited relatively low level of compatibility with Portland cement, with the rattan particles exhibiting relatively higher degree of inhibition. The addition resulted in reduced setting time (about 60%), increased hydration temperature (50–80%), lower inhibitory index and higher rate of heat generation in all the aggregate/cement mixtures. Recommendations for further research include the identification of the cement-inhibitory chemicals present in coconut husk and rattan and investigations on the mechanism of CaCl2 interaction with rattan/cement and coconut husk/cement systems
Keywords:calcium chloride; canes and rattans; cement; coconuts; composite boards; h