The Effect of Pozzolanic Waste of Different Nature on the Hydration Products, Structure and Properties of Hardened Cement Paste

Abstract

The paper analyses the effect of different pozzolanic waste -ground waste glass, metakaolin and addition made of ground waste glass and metakaolin, on cement hydration and physical-mechanical properties of hardened cement paste. Four batches of specimens were made for the tests. Cement (C) in the cement matrix was replaced with 5 % of ground waste glass (5S), 15 % of metakaolin and mixed pozzolanic was addition (MIX 20) made of 5 % of ground waste glass and 15 % of metakaolin. The best improvement of mechanical properties after 90 days of curing was observed in the specimens modified with the mixed pozzolanic addition. X-ray, TGA tests and microstructure analysis revealed that the improvement of mechanical properties is caused by the higher content of hydration products and a strong contact zone between glass particles and foam glass splinters present in metakaolin waste addition. The formation of C-S-H hydrates on the surface of glass foam splinters and in the pores was also observed. This kind of microstructure formation has a positive effect on cement matrix microstructure and physical-mechanical properties of hardened cement paste.

The Effect of Crushed Glass and Metakaolin Waste in the Properties of Modified Concrete

“…The density of concrete reduces with higher metakaolin content. The biggest drop in density was observed when 30 % of Portland cement was replaced by metakaolin [19][20][21].…”