Abstract:

To reduce cement consumption， promote solid waste utilization， and enhance both the strength and ductility of engineered cementitious composites （ECC）， this study investigated the effects of partially replacing cement with a ternary blend of rice husk ash （RHA）， rice straw ash （RSA）， and corn straw ash （CSA） on the static mechanical properties of ECC. Based on the principles of orthogonal experimental design， 9 groups of multi-component blended green ECC mixtures were designed. Uniaxial tensile， cubic compressive， and four-point bending tests were conducted to analyze the influences of RHA， RSA， and CSA at different replacement ratios （0%， 5%， and 10%， mass fraction） on various mechanical performance indicators of ECC. Furthermore， a predictive model for the static mechanical properties of the ternary-blended green ECC was established. Results indicate that the mixture containing 5% RHA and 5% CSA exhibits the best mechanical performance， compared with the control. Its 28 d tensile strength， ultimate tensile strain， and flexural load capacity increase by 15.31%， 46.64%， and 24.45%， respectively. RHA was the dominant factor influencing tensile behavior， while CSA mainly affects compressive and flexural strength； the influence of RSA is minimal. Regression models developed for compressive strength and tensile strain showed good accuracy， providing theoretical support for utilizing agricultural waste ashes in green ECC.

Key words: engineered cementitious composite, agricultural waste ash, orthogonal experimental, static mechanical property, performance prediction