Development of Eco-Efficient Composite Cements with High Early Strength

It was shown that a significant reduction of CO2 emissions in construction is achieved through the using of composite cements with a lower clinker factor. A quaternary composite cements (clinker factor -50%) containing granulated blast furnace slag, natural zeolite and limestone has been presented. The composition and particle size distribution of the constituents are optimized by the incremental coefficient of the surface activity. Synergistic combination of fine mineral additives and fillers in composite cements ensures the formation of dense microstructure of paste. It is shown that the addition of microsilica (MS) and polycarboxylate ether (PCE) admixtures ensures the production of higher strength cements. In order to accelerate the process of hydration of cement at an early age, the suspension of the C-S-H (X-Seed) nanoparticles was introduced. The effectiveness of a MS - C-S-H - PCE admixture in the early strength development of composite cement with zeolite was investigated. It has been found that the addition of MS - C-S-H - PCE significantly increases the compressive strength of cement mortar, particularly at 12-24 h of hydration. XRD and SEM measurements confirm that the hydration of composite cement is greatly accelerated. Based on the obtained results, high quality eco-efficient composite cements with high early strength can be produced.