Study on basic mechanical properties of desert sand engineered cementitious composites and seismic performance of strengthened brick masonry walls

To reduce the cost of Engineered Cementitious Composites (ECC), desert sand from Xinjiang was used as fine aggregate to produce ECC, and normal sand ECC (NS-ECC) was used as a control to evaluate the basic mechanical properties of desert sand ECC (DS-ECC). DS-ECC was then used to strengthen brick masonry walls with a relatively high aspect ratio of 0.95. One unstrengthened wall and four strengthened wall specimens were fabricated. The seismic performance of the strengthened walls using four methods, namely single-sided, double-sided, integral overlay, and strip confinement, was systematically investigated under cyclic loading. The test results indicated that DS-ECC also achieved favorable mechanical properties compared with NS-ECC, verifying the feasibility of using desert sand as a substitute for natural sand in ECC production. The four strengthened specimens effectively mitigated the brittle failure behavior of the walls. Walls with a high aspect ratio are prone to shear-compression failure, which limits the full utilization of the mechanical advantages of DS-ECC. DS-ECC provided a modest improvement in load-bearing capacity but considerably enhanced the ductility index. The cumulative energy dissipation of the double-sided integral overlay was slightly higher than that of the single-sided integral overlay, while integral overlay strengthening outperformed strip confinement. For walls with a high aspect ratio, integral overlay strengthening is recommended as the optimal reinforcement scheme.