Response Surface Methodology Optimization of Palm Rachis Biochar Content and Temperature Effects on Predicting Bio-Mortar Compressive Strength, Porosity and Thermal Conductivity

Abstract

Since cement manufacturing contributes significantly to CO2 pollution worldwide, biochar provides a novel opportunity to integrate it into the construction materials and eventually substitute a portion of cement usage. Consequently, this investigation aims to explore the response surface methodology (RSM) to predict compressive strength and identify optimal values for each parameter that affects the preparation of bio-mortars cement with biochar produced from Washingtonia filifera waste pyrolysis (WFWB). The status of the 7-days and 28-days samples compressive strength, porosity, as well as thermal conductivity of the bio-mortars produced by partially substituting cement at different rates (0%, 1%, 2%, 3%, 4%, and 5%) with pyrolyzed WFWB biochar at varying temperatures (300°C, 400°C, and 500°C) were examined experimentally and statistically. Moreover, the parameter effect on the experimental data performance was identified through analysis of variance (ANOVA). Results indicated an increase in the compressive strength at 28 days of almost 12%, 3%, and 2% at an optimum biochar content of 1% for the WFWB500, WFWB400 and WFWB300 samples respectively. In addition, the findings confer the feasibility of producing bio-mortars with a compressive strength of 63.81 MPa at 28 days with a 1% replacement rate of WFWB500 and coefficient of thermal conductivity of 0.52 W/m.K.

Keywords

• cement mortar
• washingtonia filifera waste biochar
• compressive strength, thermal conductivity, optimization
• response surface methodology