Marble Filler: Does It Retard the Dissolution of Cement Constituents?

We showed In previous studies, that partial substitution of Portland cement with fillers from industrial by-products, slag and marble, have enabled the development of new hydraulic cements (ternary or quaternary) with a good mechanical performance, in addition to their economic and ecological benefits. This paper examines the influence of partial Portland cement replacement (CEM-I) with marble filler and other mineral additions on physicochemical properties of cement paste. A rapid preliminary test, the pH measurement of a binder suspension, reveals that marble powder lowers the pH of the cement. The solutions were stirred for 24 hours, the pH was recorded automatically. The hydration kinetics changed completely; it appears that even the slow setting phase disappears. To confirm the results, tests were carried out on mortars with partial substitution of Portland cement with fillers: measurement of shrinkage, swelling, and strength. The evolution of crystalline phases was monitored by XRD, and the portlandite content (Ca(OH)2) at 28 days was determined indirectly by thermal gravimetric analysis and differential thermal analysis (TGA and DTA). The characterization methods indicate that marble filler retards various cement constituents from passing into solution.