Investigating the Performance of Alkali-Activated Cementitious Materials Under Temperature Cycling.

Yan Liu; Zeqing Hou; Ziye Feng

This study aims to explore the effects of temperature cycling on the performance of alkaliactivated fly ash-slag cementitious materials (AAFS) under various slag contents, alkali concentrations, and alkali modulus conditions. Through analyses using XRD, SEM, and FT-IR, the research examines the evolution of mass loss, drying shrinkage characteristics, and compressive strength of AAFS subjected to 60°C temperature cycles. The findings reveal that temperature cycling significantly promotes the hydration reaction of AAFS, enhancing its compressive strength, particularly after 60 cycles of temperature exposure. The hydration products C-S-H and C-A-S-H contribute positively to compressive strength, with notable effects observed from 0 to 60 cycles. Increasing slag content magnifies its impact on AAFS performance, reducing mass loss and increasing both shrinkage rate and compressive strength. When the slag content reaches 100%, the rate of mass loss during temperature cycling is minimized, and both drying shrinkage and compressive strength are significantly improved. However, the effect becomes less pronounced when the slag content exceeds 50%. Higher alkali concentration and modulus lead to an increased matrix density, yet the compressive strength of AAFS peaks at an alkali concentration of 6% and a modulus of 1.0, due to a reduction in [SiO4]4- ions and a shift from dual to single activation. Considering both economic and practical aspects, it is recommended to use AAFS combinations with no more than 50% slag content, an alkali concentration of 6%, and an alkali modulus of 1.0. These discoveries provide theoretical support for the application of AAFS in specific environmental conditions.

COMPRESSIVE strength; CYCLING competitions; DENSITY matrices; X-ray diffraction; LEAD; TEMPERATURE effect; SLAG; SLAG cement

International Journal of Heat & Technology, 2024, Vol 42, Issue 2, p490

0392-8764

Academic Journal

10.18280/ijht.420215