Waste marble dust: An interesting residue to produce cement

Abstract

The objective of the present study was to establish the technological and regulatory viability of using marble industry waste as additive in Portland cement. Six clinker and marble dust mixtures were prepared (M-1 = 0%; M-2 = 5%; M-3 = 10%, M-4 = 15%; M-5 = 20%, M-6 = 25%), varying the percentage of marble dust added from 0 to 25% of total clinker weight in the cementing mixture. Results obtained showed that the mineralogical composition of marble dust is based on the presence of CaO, and physicochemical analysis confirmed its feasibility as a pure and clean by-product. Regarding the fresh state of the cement samples, it is interesting to note that i) The paste workability varies according to the percentage addition, and water percentage values are similar to or lower than those in the control series, and ii) Expansion values of samples with marble dust addition are the same as those of the control series, with samples M-2, M-4, and M-6 reaching a value of 1 mm. Moreover, flexural-tensile strength test results at 365 days are identical for samples M-1, M-2, and M-3 to those for the control series. Flexural-tensile strength resistance data are always lower for samples M-4, M-5, and M-6 than for the control series, although this difference is reduced at higher curing ages. Compression resistance is higher in samples with percentage additions up to 10% than in the control series. Compression resistance at curing ages of 90 and 365 days was >50% of reference resistance values at 28 days. The most important conclusions regarding the cementing mixture presented in this study are that: i) it meets physicochemical criteria for the utilization of marble dust as by-product in the preparation of CEM-II cement; ii) it meets the criteria in UNE-EN 196-3 for any resistance class according to tests conducted on the cementing paste in fresh state; and iii) it can be classified as CEM-II in accordance with RC-16 guidelines, with a resistance class that varies as a function of the percentage addition of marble dust. Finally, with respect to the technical feasibility of using ornamental marble fabrication waste as additive to clinker to form a cementing mixture, the optimal percentage addition is 10% to obtain CEM-II (32.5 N), CEM-II (32.5 R), and CEM-II (42.5 N).