Ternesite is synthesized through sintering a mixture of CaCO₃, SiO₂, and CaSO₄ in a molar ratio of 4:2:1. Ternesite has a hydration rate between ye’elimite and belite in an aluminum-containing environment, and is considered to be a new material that can be used to enhance the performance of calcium sulphoaluminate cements. This experiment investigated the influence of different particle sizes of SiO₂ on ternesite formation. Controlled partial pressure sintering was employed within the temperature range from 1100 °C to 1200 °C, with a 72 h incubation period. The highest purity of ternesite in the samples reached 99.47% (500 nm SiO₂ sample). The analysis results from scanning electron microscopy and an energy dispersive spectrometer indicated that the particle size of SiO₂ exerted a significant influence on the formation of ternesite. In the preparation of ternesite from 10 μm particle size SiO₂, traces of calcium silicate were found in the product. The results of a thermal analysis further demonstrated significant distinctions in the thermal stability of ternesite prepared with SiO₂ of different particle sizes. Additionally, the crystallinity of ternesite was influenced by the particle size of SiO₂, consequently impacting the hydration performance of ternesite–calcium sulphoaluminate cement.

This study investigated the coupled effects of petroleum coke residue (PCR) and alkali equivalent on the strength, shrinkage, and durability of alkali–activated mortars based on a ground–granulated blast–furnace slag–fly ash (GGBS–FA) system. A suitable PCR content improved compressive and flexural strength, whereas higher contents reduced strength. These trends may reflect changes in calcium– and sulfate–bearing reaction products and the concurrent reduction in FA–derived precursors. Increasing the alkali equivalent generally increased strength and shrinkage, while PCR replacement generally reduced post–demolding sealed contraction. Potentially expansive products may contribute to this reduction. At 3% PCR, relatively low carbonation depths and non–steady–state chloride migration coefficients were obtained, whereas higher PCR contents could yield higher sulfate corrosion–resistance coefficients under certain conditions. An appropriate PCR dosage can effectively improve strength, shrinkage resistance, and durability, indicating potential for PCR valorization in alkali–activated mortars.