Sustainable engineered cementitious composites with waste brick and marble: mechanical and microstructural performance Available to Purchase

The utilisation of waste bricks (WB) and waste marble (WM) in engineered cementitious composites (ECCs), which are high-ductility fibre-reinforced cementitious composites, was investigated in this work. To produce sustainable ECC, WB and WM were used as cement and sand replacements, respectively. Nine ECC mixtures were produced and evaluated through tests for fresh properties, compressive and flexural strength, mid-span beam deflection and ultrasonic pulse velocity, along with microstructural analyses (Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy). The results showed that the irregular shapes of WB and the high surface area of WM reduced the workability of the ECC. WB reduced hydration products (calcium silicate hydrate and calcium hydroxide) owing to its low reactivity, which weakened the matrix and lowered its mechanical strength. The incorporation of WM resulted in enhanced mechanical strength owing to its effective filling of voids. WB enhanced ductility, with the highest value at 30% replacement, whereas WM caused a slight reduction. Microstructural tests confirmed that WB increased internal voids, while the incorporation of WM led to a denser structure. The combined use of WB and WM resulted in lower mechanical performance than their individual use owing to competing microstructural mechanisms. Based on the overall mechanical, microstructural and sustainability performance, the most favourable results were obtained by using 30% WB instead of cement and 100% WM instead of sand.