Effects of Water Content on Compressive Strength of Ecofriendly Light-weight Cement Blocks Using Cement-like Material Prepared from Agricultural Wastes

Abstract

Limestone quarrying process is recognized as an initial step in cement production, which produces high content of dust and creates detrimental effects on both the environment and human health. Utilization of agricultural wastes as alternative raw materials is one of the routes to solve such problem. This research is intended to produce eco-friendly light-weight cement blocks from a cement-like material. The cement-like material was synthesized by the low-energy consumption solution combustion technique, using cockleshell and rice husk ash as raw materials. Phase identification analysis of the synthesized cement-like powder indicated the expected phases of tri-calcium silicate (C3S), di-calcium silicate (C2S), tri-calcium aluminate (C3A), and tetra-calcium alumino ferrite (C4AF). To fabricate eco-friendly light-weight cement blocks, the synthesized powder was mixed with Ordinary Portland Cement (OPC), rice husk ash (RHA) and water, with the weight ratio of the synthesized powder:OPC:RHA equal to 25:25:50. The mixture was subsequently cast into light-weight cement blocks. Effects of water contents on compressive strength and bulk density of the light-weight cement blocks were examined. Experimental results revealed that compressive strength of the samples ranged between 1.1 MPa and 2.1 MPa, whereas density ranged from 1.01 g/cm3 to 1.14 g/cm3. The compressive strength of the samples in this study were in a comparable range with that of light-weight concrete defined by Thai Industrial Standards Institute (TISI) and American Concrete Institute (ACI 213,2001). The optimal condition to achieve the standard properties of light weight cement blocks is water-to-binder ratio of 1.3:1 by weight. Results from the current study, therefore, suggested that the eco-friendly light-weight cement blocks obtained from this study exhibited potential practical usage.