Modifying the pore size distribution in Fe-rich inorganic polymer mortars: An effective shrinkage mitigation strategy. (March 2021)

• Record Type: Journal Article
• Authors: Beersaerts, G.; Ascensão, G.; Pontikes, Y.
• Is Part Of: Cement and concrete research. Volume 141(2021)
• Publication Date: 2021-03
• Subjects: Fe-rich slag -- Alkali-activated materials -- Inorganic polymers -- Autogenous deformation -- Drying shrinkage; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2020.106330
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: Inorganic polymer (IP) binder is formed upon alkali-activation of Fe-rich (41 wt%) metallurgical slag leading to materials with mechanical properties comparable to ordinary Portland cement binders. Crack formation is reported in IPs, which can be related to volumetric stability, which is to date not thoroughly understood in IPs. This study determined the autogenous and drying shrinkage of IP mortars. Shrinkage mitigation strategies, such as the addition of 2-methyl-2, 4-pentanediol (2MPL), blast furnace slag (GGBFS), and applying heat curing, were used separately or in combination. IP mortars exhibited autogenous expansion and high drying shrinkage. The addition of 2MPL led to a porosity increase, as air was entrained, decreasing the drying shrinkage with 64%. Additional heat curing had no effect on samples with 2MPL. Introducing GGBFS resulted in smaller pores, increasing drying shrinkage. Shrinkage in IP mortars is driven by its pore size distribution and higher shrinkage resulted in lower flexural strength. Graphical abstract: Unlabelled Image Highlights: Inorganic polymer mortar has mainly macropores and a drying shrinkage of 5.1 mm/m. 2-methyl-2, 4-pentanediol acts as air entrainer in inorganic polymer mortars. Optimal dosage 2 wt% 2-methyl-2, 4-pentanediol reduced drying shrinkage to 1.8 mm/m. Heat curing inorganic polymer mortars reduced drying shrinkage more than 50%. Blast Furnace slag addition increased drying shrinkage and reduced strength.