Effectiveness of saw dust ash and cement for fabrication of compressed stabilized earth blocks

Abstract

This study focuses on investigating the effectiveness of Saw Dust Ash (SDA) and cement for fabricating strong and durable Compressed Stabilized Earth Block (CSEB) using coarse-grained soil. CSEB is a viable alternative to traditional Fired Clay Brick (FCB) as warranted by reduced associated pollution and increased energy efficiency. Four different cement contents (4%, 6%, 8% and 10%) and different SDA contents (0–10%) are considered to discern optimum combination to fabricate satisfactory CSEB in terms of compressive strength, shear strength, deformation behavior and durability. For a particular cement content, addition of SDA increases the compressive strength gradually, reaches a maximum value which is identified as optimum content and thereafter begins to drop. Optimum amount of SDA was found 4% for 4% cement, 6% for 6–8% cement and 8% for 10% cement. Addition of cement-SDA is found to increase the compressive strength of the blocks by 21–147% compared to that of unstabilized earth blocks. Moreover, optimum combination of cement-SDA provides CSEBs with maximum density and minimum porosity. Inclusion of cement-SDA is found effective in increasing angle of internal friction, ϕ of the stabilized mix. With addition of optimum SDA (4–8%) with cement, mixtures were found to exhibit ϕ>58o. CSEBs with optimum amount of cement-SDA is found to provide maximum modulus of elasticity, peak strain and failure strain. Addition of 6–8% SDA with 6–10% cement is found durable in terms of water absorption (<15%), wet compressive strength (>700 kPa) and wet-to-dry strength ratio (>0.33). Based on all the parameters and obtained test results, it can be concluded that cement-SDA stabilized earth blocks can be efficiently considered as a suitable construction material.