A Comparative Study on the Degradation of Alkali-Activated Slag/Fly Ash and Cement-Based Mortars in Phosphoric Acid

A Comparative Study on the Degradation of Alkali-Activated Slag/Fly Ash and Cement-Based Mortars in Phosphoric Acid

Ren, Jie (University of Melbourne; University of Colorado)
Zhang, Lihai (University of Melbourne)
Zhu, Yingcan (University of Southern Queensland)
Li, Z. (TU Delft Materials and Environment)
San Nicolas, Rackel (University of Melbourne)

2022

This study compares the degradation behavior of the alkali-activated slag/fly ash (AASF) and ordinary Portland cement (OPC) mortars exposed to phosphoric acid with different pH values. The experimental results show that AASF mortars exhibit better resistance than OPC mortars against surface damage, although both systems get white deposits on the surface in phosphoric acid with a relatively high pH level. AASF mortars obtained lower mass loss than OPC mortars in phosphoric acid with pH at 2 and 3. The strength reduction in AASF mortars after immersion in phosphoric acid is more significant than that in OPC mortars. However, total degradation depth of AASF was smaller than that of OPC regardless of the pH of the acid solutions. Based on the experimental data, linear relationships were identified between the slope of degradation depth–mass loss curves and the Al/Si and Ca/Si ratios of the binders. This may indicate a new way to assess the degradation behavior of AASF and OPC based on their chemical compositions.

alkali-activated materials
Portland cement
phosphoric acid
degradation
strength

http://resolver.tudelft.nl/uuid:501de7eb-16e3-4c3c-98de-6366654b965a

https://doi.org/10.3389/fmats.2022.845349

2296-8016

Frontiers in Materials, 9

Institutional Repository

journal article

© 2022 Jie Ren, Lihai Zhang, Yingcan Zhu, Z. Li, Rackel San Nicolas