Effect of rice straw ash at different burning temperatures on high-strength concrete properties
摘要
The increase in global agricultural production is accompanied by an increase in agricultural waste (AW), including ash from this waste. To protect the environment, it is necessary to dispose of agricultural waste safely and sustainably. This study explores the use of AW ash, specifically rice straw ash (RSA), as a partial cement replacement for producing eco-friendly high-strength concrete (HSC). The RSA was subjected to heat treatment for 120 min at temperatures of 400 °C, 500 °C, 600 °C, 700 °C, and 800 °C to improve its chemical and physical properties. To evaluate the efficiency of heat treatment, the effect of replacing different levels of RSA at 10%, 15%, and 20% of cement mass on the properties of HSC was studied. To evaluate the processing efficiency of RSA, the HSC samples were tested for slump, compressive strength (CS), splitting tensile strength (STS), flexural strength (FS), modulus of elasticity (ME), water permeability (WP), water sorptivity (WS), and chloride penetration (CP), in addition to the microstructure characteristics. Heat treatment of RSA allowed it to replace up to 20% by cement weight while producing superior HSC properties compared to the reference mix. Heat treatment of RSA at 700 °C decreased the LOI and, at the same time, increased the pozzolanic (Si2O + Al2O3 + Fe2O3) content to 82%. HSC (700 °C-15%) achieved a CS of 78.6 MPa, while the reference mixture was 69.5 MPa.