Experimental study on the performance of lime-based low carbon cementitious materials

Abstract

In this study, a novel type of lime-based low carbon cementitious material (LCM) was designed and prepared using low contents of hydrated lime and Portland cement and a high content of mineral admixtures. The mechanical properties, workability, heat of hydration, hydration degree, porosity, hydration products, and microstructure of LCM were systematically investigated. The test results indicated that LCM showed good mechanical properties and workability compared with conventional blended cement. The compressive strength of LCM can achieve 50–60 Mpa at curing 28 d and more than 70 Mpa at curing 180 d. The hydration products of LCM were mainly composed of ettringite, portlandite, and C–(A)–S–H gel according to X-ray powder diffraction results. Analysis suggests that a small amount of Portland cement in LCM accelerated the pozzolanic reaction of mineral admixtures due to the alkalinity, and the Ca2+ ion concentration in the pore solution increased. Meanwhile, the hydrated lime reacted with mineral admixtures in long-term hydration and increased the mechanical property of LCM. In addition, LCM exerted a notable reduction in carbon emission, energy consumption and environmental burden compared with Portland cement. The quantitative calculation suggested that the energy intensity and carbon emission of the LCM are only approximately 24–45% and 13–38% that of Portland cement, respectively.