The mineral structure and performance of belite-barium calcium sulphoaluminate cement clinker were investigated by petrographic analysis, X-ray diffraction and scanning electron microscopy, while raw materials were studied by differential thermal analysis, thermogravimetric analysis and X-ray diffraction. The results show that high-silicon limestone has low decomposition temperature which can promote the development of alite by adding small quantity. The formation and development of C3S is hindered in α-quartz while C3S is formed easily by mixing magnesite and dolomite in the low temperature. The proper proportions of high-silicon limestone and ordinary limestone is 1:5, and the compressive of this cement at 3, 7, 28 d are 37.9, 60.3, 87.9 MPa, which shows excellent mechanical properties.
The effect of MgO on performance of belite-barium calcium sulphoaluminate cement (B-CBAS) was investigated through orthogonal tests. The results show that the formation of C3S can be improved at low temperatures by mixing MgO. SO3 decreasing the viscosity of fused mass in sintering process was beneficial to solid solution of MgO in B-CBAS clinker. The solid solubility of MgO in B-CBAS was higher than that of Portland cement, which indicated that high-magnesium limestone can be used in B-CBAS. Even MgO content reached 5.14%, the soundness of B-CBAS was still in safe, whose compressive strength at 3d and 28d curing age were 49.1MPa and 81.9MPa. This indicated that this kind of cement has good mechanical properties.
The influence of anhydrite on mechanical property and alkalinity of sulphoaluminate cement clinker was investigated. The alkalinity was examined by mixing powdered samples with a solvent and measuring the pH of the suspension. The hydration mechanism was analysed by XRD analysis. The results indicated that with the increase of anhydrite addition, both the alkalinity and compressive strength decreased. Yeelimite completely converted into ettringite with the dosage of anhydrite reaching to 50% by weight of the paste. With the dosage of 30%, the 7 d pH could be reduced to 10.43 while the 7 d compressive strength was 48 MPa.
The polymer sulphoaluminate cement is composed of styrene-acrylic emulsion and sulphoaluminate cement. The resistance to sulfate attack, impermeability and mechanical performance are studied in the paper. The hardened paste microstructure of the polymer sulphoaluminate cement is studied by means of SEM. The experiment shows that the impermeability of the cement is improved with the increase of styrene-acrylic emulsion. When the ratio of polymer to cement increases from 0% to 15%, the permeate height of the hardened cement paste decreases by 70%. The resistance to sulfate attack of the cement is also improved with the increase of styrene-acrylic emulsion. Styrene-acrylic emulsion has little effect on the flexural strength of sulphoaluminate cement. When the ratio of polymer to cement is less than 15%, the flexural strength of the cement at 28d curing ages are all above 7.1MPa. As shown from SEM photographs, the cement becomes more close-grained when the ratio of polymer to cement increases.
Styrene-acrylic emulsion was synthesized by pre-emulsification and semi-continuous emulsion polymerization, with styrene and butyl acrylate as monomers. The effects of initiator dosage and ratio of polymer to cement on durability of polymeric sulphoaluminate cement were investigated. SEM, pore structure and resistance to sulfate attack were also studied. The results show that the total porosity of the polymer sulphoaluminate hardened cement paste is lowest when P/C is 7.5%. Innocuous pores of the hardened paste are the least when P/C is 5.0%. It shows that polymer particles can spread around the cement paste, and polymer particles, aggregates, hydration products and pores come into being a compact mass. Flexural strength is higher when initiator dosage is 5‰ than that is 4‰. Flexural strength is the highest when initiator dosage is 5‰ and P/C is 7.5%, in other words, the performance of resistance to sulfate attack is best when initiator dosage is 5‰ and P/C is 7.5%.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.