Mechanical Properties of Na2CO3-Activated High-Volume GGBFS Cement Paste

Abstract EN

The use of Na2CO3 to improve the mechanical properties of high-volume slag cement (HVSC) is experimentally investigated in this study.

Ordinary Portland cement (OPC) was replaced with 50, 60, 70, 80, and 90% ground-granulated blast-furnace slag (GGBFS) by weight.

Na2CO3 was added at 0, 1, 2, 3, 4, and 5 wt.% of HVSC (OPC + GGBFS).

The compressive strength, water absorption, ultrasonic pulse velocity, dry shrinkage, and X-ray diffraction spectra of the Na2CO3-activated HVSC pastes were analyzed.

The results indicate that Na2CO3 was effective for improving the strength of HVSC samples at both early and later ages.

There was a trend of increasing HVSC sample strength with increasing Na2CO3 content.

The 5% Na2CO3-activated HVSC (50% OPC + 50% GGBFS) paste had the best combination of early to later-age strength development and exhibited the highest UPV and the lowest water absorption among the Na2CO3-activated HVSC samples at later age.