Effect of crystalline admixtures on shrinkage and alkali-silica reaction of biochar-cementitious composites

Xuqun Lin; Arnaud Castel; Zhizhong Deng; Biqin Dong; Xuanrui Zhang; Shishun Zhang; Wengui Li

Developments in the Built Environment (Apr 2024)

Effect of crystalline admixtures on shrinkage and alkali-silica reaction of biochar-cementitious composites

Xuqun Lin,
Arnaud Castel,
Zhizhong Deng,
Biqin Dong,
Xuanrui Zhang,
Shishun Zhang,
Wengui Li

Affiliations

Xuqun Lin: School of Civil and Environmental Engineering, University of Technology Sydney, NSW, 2007, Australia
Arnaud Castel: School of Civil and Environmental Engineering, University of Technology Sydney, NSW, 2007, Australia
Zhizhong Deng: School of Civil and Environmental Engineering, University of Technology Sydney, NSW, 2007, Australia
Biqin Dong: College of Civil and Transportation Engineering, Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Guangdong, 518060, China
Xuanrui Zhang: School of Civil and Environmental Engineering, University of Technology Sydney, NSW, 2007, Australia
Shishun Zhang: School of Civil and Hydraulic Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
Wengui Li: Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, NSW, 2052, Australia; Corresponding author. Centre for Infrastructure Engineering and Safety, School of Civil and Environmental Engineering, The University of New South Wales, NSW, 2052, Australia.

Journal volume & issue: Vol. 18
p. 100456

Abstract

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This study investigated effects of crystalline admixture (CA) on shrinkage and alkali-silica reaction behaviours of biochar-cementitious composites. Addition of 1–1.5 wt% superabsorbent polymer (SAP) completely mitigated autogenous shrinkage while slightly increasing the 120-day total shrinkage of the SP-cement composite by 5.7%, resulting in the highest apparent porosity. 1–1.5 wt% CA addition did not affect autogenous shrinkage while slightly reducing the 120-day total shrinkage by 10.1%. The combination of CA and waste wood biochar (WWB) reduced autogenous shrinkage by 24.23% and 120-day total shrinkage by 23.6%, resulting in the lowest apparent porosity. The formation of hydration products in the WWB pores and on WWB surface densified the cementitious matrix, leading to a reduction in water evaporation. Furthermore, for specimens exposed to 1 M NaOH solution at 80 °C, CA addition significantly reduced the 120-day expansion by 50.6%, while the combination of CA and WWB addition reduced the 120-day expansion by 42.9%.

Published in Developments in the Built Environment

ISSN: 2666-1659 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Engineering (General). Civil engineering (General); Technology: Building construction
Website: https://www.journals.elsevier.com/developments-in-the-built-environment/

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