The use of waste marble for cleaner production of structural concrete: A comprehensive experimental study

Waste marble is a byproduct that is produced as a result of cutting and reshaping marble stone that is commonly used in the construction sector. From a sustainability perspective, waste marble can be a potential alternative to limestone sand with slightly reduced ecological footprint which is aligned with novel concepts, such as circu-larity of construction industry. To provide a comprehensive outline of marble's use as coarse aggregate in concrete production, this study adopted utilizing waste coarse marble aggregate (WCMA) at a quantity of 50% and 100% to substitute coarse limestone aggregates (also natural coarse aggregate (NCA)). Likewise, since marble stone is considered as a metamorphic rock with slightly different microspores, compared to limestone, three different water-to-cement ratios (w/c) of 0.35, 0.42 and 0.49 have also been used. Results show that concretes incorporating WMCA exhibit a slightly better mechanical performance than concretes incorporating NCA, given that the w/c ratio is enough to lubricate WMCA's surface but not to the point of increasing free water in concrete's microstructure. In other words, it is found that WMCA is relatively sensitive to the mixture's w/c ratio which can have a large impact on the resulting physico-mechanical and thermo-durability properties of the specimens. In this regard, despite the WMCA's slightly enhanced performance in certain thermo-durability tests, the interfacial transition zone (ITZ) areas are found to be more susceptible to deteriorating factors. Nonetheless, the result of this study is found to be significant and point to the suitability of utilizing WMCA as an alternative to NCA.