Tribochemical and thermal activation of α-C₂S hydrate as precursor for cementitious binders

In this paper, the favorable chemical composition of alternative hydraulic cementitious binder (HCB) consisting of synthetic α-C2S hydrate and quartz, as well as the impact of tribochemical—thermal treatment on HCB properties was determined. Hydraulic cementitious binder was prepared by mixing synthetic α-C2S hydrate and quartz sand (the ratio was equal to 1:1 by mass), homogenizing in a homogenizer at 34 rpm for 30 min. Tribochemical activation was carried out in vibratory disk mill at 950 rpm for 2, 5, 10, and 20 min. It was estimated that the tribochemical activation affects the properties of HCB because a higher fineness provides a greater surface area to be wetted, and also results in an acceleration of the reaction between HCB and water. It was determined that the favorable tribochemical activation time for α-C2S hydrate is 5 min. Meanwhile, the investigation of the influence of quartz quantity in composition showed that at least 50 % of it is essential. Also, these studies showed that coupled application of tribochemical and thermal activation helps to create HCB samples with higher reactivity. In addition, it was determined that the best conditions are when α-C2S hydrate and quartz sand ratio is 1:1, tribochemical activation time in vibratory disk mill at 950 rpm: 5 min, thermal activation temperature: 450 °C, duration: 30 min. HCB made under these conditions has 3.7 m Wg−1 of heat flow and is similar to Portland cement.     «

In this paper, the favorable chemical composition of alternative hydraulic cementitious binder (HCB) consisting of synthetic α-C2S hydrate and quartz, as well as the impact of tribochemical—thermal treatment on HCB properties was determined. Hydraulic cementitious binder was prepared by mixing synthetic α-C2S hydrate and quartz sand (the ratio was equal to 1:1 by mass), homogenizing in a homogenizer at 34 rpm for 30 min. Tribochemical activation was carried out in vibratory disk mill at 950 rpm...     »