Engineering properties of lightweight cellular cemented clay−fly ash material

Abstract

Lightweight Cellular Cemented (LCC) material has wide applications in infrastructure rehabilitation and in the construction of new facilities. The roles of water content, cement content, air content, and fly ash (FA) replacement on the engineering properties, including unit weight, flow and strength of LCC clay−FA material, are investigated, analyzed and presented in this article. The engineering properties are strongly controlled by the generalized stress state, w/wL, where w is the water content and wL is the liquid limit. The FA replacement reduces wL, resulting in a change in w/wL. The workable state, recommended to produce the LCC clay−FA material, is w>1.5wL. The flowability is independent of cement content and approximated in terms of w/wL and air content in logarithmic function. The void/cement ratio (V/C), defined as the ratio of the void volume to the cement volume in the mix, is found to be the dominant parameter governing the strength development in LCC clay−FA material. The fabric (arrangement of clay particles, clusters and pore spaces) reflected from both air foam content and water content is taken into consideration by the void volume while the inter-particle forces (levels of cementation bond) are governed by the input of cement (cement volume). A strength equation in terms of V/C at a particular curing time is introduced using Abrams’ law as a basis. From the critical analysis of test results, a mix design method to attain the target unit weight, flowability and strength is suggested. This method is beneficial from both engineering and economic viewpoints.