Comparative analysis of rice husk ash and saw dust ash on tensile strengths of concrete
Date
2015-12
Authors
Journal Title
Journal ISSN
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Publisher
Federal University of Technology, Owerri
Abstract
This study focuses on the comparative analysis of rice husk ash (RHA) and saw dust ash (SDA) on tensile strengths of concrete. RHA and SDA were obtained from open burning. The physical properties and chemical composition of the ashes were investigated. Ordinary Portland cement (OPC) was replaced with RHA, SDA, and RHA-SDA at 5%, 10%, and 15%. Concrete mix design was done using SCALE149 (Structural Calculations Ensemble) Software. Nine concrete cylinders of dimension 150×300mm with 100% OPC or 0% replacement with pozzolan were produced. Eighty one concrete cylinders were also produced for each of the percentage replacement of OPC with RHA, SDA, RHA-SDA, making a total of 252 concrete cylinders. The concrete cylinders were cured by immersion and tested for split tensile strength at 28, 90, and 150 days. The results showed that RHA is a better pozzolana with combined (SiO2 + Al2O3 + Fe203) of 87.67% compared to SDA which was 50.03% . The Split tensile strength decreased with increasing RHA, SDA, and RHA-SDA OPC percentage replacement. Laboratory values of 0.86N/mm2 and 0.78N/mm2 were obtained at 5% and 10% RHA-OPC replacement, 0.77N/mm2 and 0.58N/mm2 were obtained at 5% and 10% SDA-OPC replacement. Similarly, 0.82N/mm2 and 0.64N/mm2 were obtained at 5% and 10% RHA-SDA-OPC replacement. Split tensile strength of concrete with RHA, SDA, and RHA-SDA were lower at early age of curing but improved at later ages of curing. For example, at 5% RHA-OPC replacement, 1.42N/mm2 and 1.85N/mm2 were obtained at 90 and 150 days of curing. At 5% SDA-OPC replacement, 1.28N/mm2 and 1.65N/mm2 were obtained at 90 and 150 days of curing. Similarly, at 5% RHA-SDA-OPC replacement, 1.35N/mm2 and 1.66N/mm2 were obtained at 90 and 150 days of curing, as against 1.34N/mm2 and1.61N/mm2 attained by the control at 90 and 150 days of curing. Models were developed to predict the tensile strengths of concrete containing RHA and SDA as binary and ternary blend with OPC at varying percentage replacements and curing ages. The models were tested and found to be adequate.
Description
This thesis is for the award of Master of Engineering (M.Eng) in Civil Engineering (Structure)
Keywords
Split tensile strength, concrete, pozzolana, rice husk ash, saw dust ash, binary blend, ternary blend, Department of Civil Engineering
Citation
Ezenkwa, C. S. (2015). Comparative analysis of rice husk ash and saw dust ash on tensile strengths of concrete [Unpublished Master's Thesis]. Federal University of Technology, Owerri , Nigeria