Effects of Water-to-Cement and Sand-to-Binder Ratio on Mechanical and Drying Shrinkage Properties of Low-Carbon Mortar Containing Biochar Aggregate
Year: 2025
Type: article
Abstract: Biochar, serving as a carbon sequestration material, has garnered significant attention. In this study, the effects of water-to-cement (W/C) and sand-to-binder (S/B) ratio on the macroscopic mechanical properties, dry-shrinkage behavior, and water transport properties of biochar mortar, as well as the microstructure of the mortar, are described. The results indicate that the compressive strength of the mortar decreases gradually with increases in the S/B ratio, while its flexural strength increases gradually with increases in the S/B ratio. Meanwhile, with increases in W/C and S/B, the drying shrinkage rate decreases, and the extent of water loss tends to be comparable to the drying shrinkage rate. The water absorption of biochar mortar increases as the W/C and S/B ratios increase. This is also reflected in the depth of water ingress in biochar mortars, which increases significantly with rising W/C and S/B ratios. Moreover, the water absorption coefficients of different mortars vary significantly only in the first few hours, and their final water absorption coefficients and ingress depths are similar. The SEM results indicate that biochar can provide nucleation points for hydration products to form a unique binding mechanism between them and the cement matrix. In addition, when the sand-to-cement ratio reaches 1.15, biochar reduces CO2 emissions by 104.57 kg, and biochar mortar shows good potential for CO2 sequestration.
Source: Materials
DOI: 10.3390/ma18122750
Authors: Shasha Chen, Junhui Zhang, Hao Yang
Institution: Changsha University of Science and Technology
Language: English
Subfield: Civil and Structural Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W4411249520