Microstructure refinement and affected zone reinforcement for internal curing cement paste by composite microgel with nano silica. (April 2023)

• Record Type: Journal Article
• Authors: Zhang, Gengtong; Xia, Huiyun; Niu, Yanhui; Song, Lifang; Zhao, Yuanlong; Lv, Xin; Chen, Huaxin; Cao, Dongwei
• Is Part Of: Cement & concrete composites. Volume 138(2023)
• Publication Date: 2023-04
• Subjects: Composite microgels -- Nano silica -- Pore structure -- Affected zone -- Compressive strength; Composite-reinforced concrete -- Periodicals; Concrete -- Periodicals; Composite materials -- Periodicals; Composites de ciment -- Périodiques; Béton -- Périodiques; Composites -- Périodiques; Béton léger -- Périodiques; Cement composites; Composite materials; Composite-reinforced concrete; Concrete; Lightweight concrete; Periodicals; Electronic journals; 620.135
• DOI: 10.1016/j.cemconcomp.2023.105013
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: The introduction of superabsorbent polymers into cement increases the number of macroscopic pores, resulting in reduction of compressive strength. These limitations can be addressed by incorporated nano silica in polymer structure. Herein, a series of composite microgels containing nano silica were prepared and incorporated into cement paste. The effect of composite microgels on the hydration degree, compressive strength of cement paste was investigated. The microstructure and affected zone of cement paste were characterized by nitrogen adsorption desorption (NAD), backscattering (BSE), thermogravimetry (TGA) and microhardness techniques. The equilibrium absorptivity and water release rate of the composite microgels can be improved by proper crosslinking density and silica content. The addition of low crosslinking density composite microgels accelerated the formation of hydration products, which encouraged to filling formed voids. More dense arch structure was observed in vicinity of formed void. These further suggested that the reduction in the compressive strength of cement paste can be offset by composite microgels with proper crosslinking density, thus providing important application prospects in internal curing.