Comparison of the effect of ground waste expanded perlite and silica fume on the hydration of cements with various tricalcium aluminate content – Comprehensive analysis
Ewa Kapeluszna, Łukasz Kotwica, Wiesława Nocuń-Wczelik
Abstract
The influence of ground waste expanded perlite (WEP) and silica fume on the hydration of two cements containing 2% and 7% of C3A was investigated. The effect of additives was different depending on the C3A content, especially at the early stage of hydration. Aluminates hydration was strongly affected, which manifested in the alteration of the aluminate calorimetric peak related to the renewal hydration of C3A. In the presence of pozzolans, the amount of Ca(OH)2 was reduced and more C-S-H was formed. Therefore, the compressive strength increased and the porosity decreased. The correlation between the early compressive strength and the heat of hydration as a function of pozzolan content was linear only for cement with 7% of C3A. FTIR studies revealed the differences in the evolution of bands originating from WEP and silica fume during hydration. FTIR can possibly be used for the determination of pozzolanic reaction progress of the latter.