Effect of Pre-Wetted Biochar on Autogenous Shrinkage and Compressive Strength of Ultra-High Performance Concrete

doi:10.16552/j.cnki.issn1001-1625.2025.0201

Abstract

Abstract: To address the issue of compressive strength reduction in internally cured ultra-high performance concrete (UHPC), this study investigates the effects of pre-wetted biochar with different particle sizes, as a replacement for fly ash, on the fresh properties, autogenous shrinkage, compressive strength, pore structure, and microstructure of UHPC. The results demonstrate that the incorporation of pre-wetted biochar significantly enhances the internal humidity of UHPC and effectively reduces its autogenous shrinkage by 28%~55%, with smaller particle-sized biochar exhibiting superior internal curing performance. Furthermore, the internal curing water released by pre-wetted biochar improves cement hydration degree, promoting the formation of additional hydration products. This process not only enhances the densification of UHPC but also leads to marginal increases in 7 and 28 d compressive strength, thereby notably addressing the significant issue of compressive strength reduction in conventional internally cured UHPC.

Key words: ultra-high performance concrete, biochar, autogenous shrinkage, compressive strength, internal relative humidity

CLC Number:

TU528

HUANG Congbin, TAI Hongsheng, LUO Jugang. Effect of Pre-Wetted Biochar on Autogenous Shrinkage and Compressive Strength of Ultra-High Performance Concrete[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(7): 2458-2464.

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