Pore structure of mortars with cellulose ether additions – Study of the air-void structure. (September 2015)

• Record Type: Journal Article
• Authors: Wyrzykowski, Mateusz; Kiesewetter, René; Münch, Beat; Baumann, Robert; Lura, Pietro
• Is Part Of: Cement & concrete composites. Volume 62(2015)
• Page Start: 117
• Page End: 124
• Publication Date: 2015-09
• Subjects: Cellulose ethers -- Entrained air -- Image analysis -- Pore size distribution -- Pores agglomeration -- Stereology; 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.2015.04.016
• Languages: English
• ISSNs: 0958-9465

Abstract

Abstract: Polished section analysis was employed to study the pore structure of model tile adhesive mortars containing different types of cellulose ethers (CE, respectively Methyl Cellulose, Hydroxyethyl- and Hydroxypropyl-Methyl Cellulose) at different dosages (0.3% and 0.8% by dry mortar mass). Flat layers of hardened mortar applied on an absorbing substrate were studied. To enhance the visibility of the air voids, the polished cross-sections were colored in black and talcum powder was pressed into the voids. Next, flatbed scanner was used to take the images. Due to a high level of agglomeration of pores, digital detachment was necessary in order to retrieve their original shapes and sizes. A stereological reconstruction of 3-D pore size distributions was performed based on the 2-D data from section analysis. Pore shapes were analyzed by determining circularity of the 2-D pore representations, a parameter that allowed estimating the extent of pores agglomeration that occurred in the analyzed mortars. It was found that higher dosage of CE resulted in a slight volume increase and a clear coarsening of the air voids. As shown by the analysis of circularity, this is likely due to higher extent of agglomeration at higher CE dosage.