Study on Carbonation Resistance of Polymer-Modified Sulphoaluminate Cement-Based Materials

Abstract

The use of tricyclic copolymer latex (AMPS) can effectively improve the carbonation resistance of sulphoaluminate cement. This paper investigated polymer AMPS and polycarboxylic acid to modify sulphoaluminate cement materials by exploring the carbonation level of sulphoaluminate cement paste and mortar and the strength before and after carbonation. Then, the optimal dosage of polymer and polycarboxylic acid was obtained so that the carbonation resistance of sulphoaluminate cement reached the best state. The compressive strength was significantly improved by adding AMPS for sulphoaluminate cement paste and mortar. After carbonation, the strength decreased and combined with the carbonation level; it was concluded that the carbonation resistance of sulphoaluminate cement materials was the best when the optimal dosage of AMPS and polycarboxylic acid was 5% and 1.8%, respectively. Due to the addition of AMPS, the hydrated calcium aluminosilicate (C-A-S-H) and hydrated calcium silicate (C-S-H) gels, generated by the hydration of sulphoaluminate cement and the surface of unreacted cement particles, are wrapped by AMPS particles. The water is discharged through cement hydration. The polymer particles on the surface of the hydration product merge into a continuous film, which binds the cement hydration product together to form an overall network structure, penetrating the entire cement hydration phase and forming a polymer cement mortar with excellent structural sealing performance. To prevent the entry of CO2 and achieve the effect of anti-carbonation, adding polycarboxylic acid mainly improves the sample’s internal density to achieve the anti-carbonation purpose.

Mechanism of Acrylate Emulsion-Modified Cement-Based Materials

“…Ca 2+ and Na + act as a bridge between the functional group oxygen atom of hydrated calcium silicate and the silicate chain oxygen. O-Ca-O and O-Na-O salt bridges enhance interface bonding, suppress crack development, and improve the ductility of cement–polymer composites [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ].…”

“…This process forms a network structure that enhances the density and impermeability of cement-based materials, as observed in previous studies [ 7 , 78 ]. Additionally, the interface structures between organic and inorganic materials in polymer-modified cement-based materials create interactions between atoms and molecules in the polymers and the hydration products of cement-based materials through hydrogen bonds, van der Waals forces, and other mechanisms [ 20 ].…”

“…In the 1940s, products modified with polyvinyl chloride were developed to enhance the bonding strength between new and old concrete and manufacture concrete pipes [ 18 ]. Today, polymer concrete materials are still a new trend in modified cement-based materials [ 19 , 20 ]. Latex polymers such as acrylic ester (PAE), styrene–butadiene rubber (SBR), and polyvinyl alcohol (PVA) are among the non-toxic and environmentally friendly materials used for polymer modification, with high resistance to chemical corrosion and high bonding strength [ 4 , 21 , 22 , 23 ].…”