The effect of water ratio on the mechanical properties of refactory materials

Abstract

This study was carried out to investigate the effect water ratio in relation to dry mass has on the mechanical properties of refractory materials. A number of different refractory materials ranging from lightweight to dense grade were investigated for the following properties: - permanent dimensional change; - bulk density; - cold compressive strength; and - cold modulus of rupture. Water is an essential component when preparing refractory materials however with increased water ratio adverse mechanical properties developed. Each of the materials tested suffered an increase in permanent dimensional change as a result of increased water ratio between the dried and the fired state. The degree of shrinkage associated with the increase in water ratio was more significant in the dense materials. Each material tested exhibited a reduction in fired bulk density associated with an increase in water ratio. This reduction was relatively consistent across all materials tested. An increase in water ratio was associated with a reduction in each material's ability to withstand a compressive force. The cold compressive test results tended to display a more significant reduction in compressive strength for the denser materials. All materials exhibited a greater than expected flexural strength when prepared in accordance with manufacturers' recommendations. As additional water was used the cold modulus of rupture results of all materials reduced indicating that increased water ratio decreases a refractory materials ability to withstand a bending force.