Floured CaCO as Supplementary Cementitious Material in Defined Performance Concrete

The use of mineral additives (SCM) has been a major trend in concrete technology for several decades. This is due to both economic and environmental considerations. Utilization of large-capacity industrial and energy waste, and reduction of pure-clinker binders’ consumption are one of the basic principles of sustainable development in construction. In addition, the technology of high performance, self-compacting concrete requires the mandatory use of fine mineral additives. As a rule, additives with their own hydraulic or pozzolanic activity are used for this purpose, viz granulated blast furnace slag, fly ash, natural pozzolans, microsilica, etc. However, other mineral additives, in particular, calcium carbonate, can also demonstrate high efficiency in concrete mix design. The paper presents the test results of concrete mixes and concretes made using 25% fine calcite in binary blends with ordinary Portland cement CEM I 42.5. For concrete compositions with a cement consumption of 250–350 kg/m, the possibility to achieve a compressive strength of 60 – 80 MPa at the age of 28 days when hardening under normal conditions (t = 20 ± 2 ℃, φ = 95 ± 5%) is shown. For concretes that hardened under heat and moisture treatment at t = 80 ℃ for 6 h, the strength was 30–60 MPa. The high integral waterproofing of the obtained concretes was noted. The use of CaCO as an SCM allows adjusting flexibly the technological parameters of concrete mixes and the physical and mechanical characteristics of concrete, depending on the required functionality. In combination with effective polycarboxylate-based superplasticizers, fine particles of CaCO in concrete mixtures (especially self-compacting ones) can provide resistance to concrete segregation and bleeding, ensuring high rates of concrete strength gain and low permeability. Light-colored calcium carbonate polymorphs can be used effectively to save white Portland cement consumption.