Optimization of biochar and fly ash to improve mechanical properties and CO2 sequestration in cement mortar
Optimization of biochar and fly ash to improve mechanical properties and CO2 sequestration in cement mortar
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DOI：
10.1016/j.conbuildmat.2023.132021
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发表时间：
2023-08
影响因子：
7.4
通讯作者：
G. Mishra;Panagiotis A. Danoglidis;Surendra P. Shah;M. Konsta-Gdoutos
中科院分区：
文献类型：
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作者：
G. Mishra;Panagiotis A. Danoglidis;Surendra P. Shah;M. Konsta-Gdoutos
本研究的新颖之处在于寻找生物炭和高钙粉煤灰的最佳掺量，以改善水泥砂浆的力学性能，促进水泥砂浆对二氧化碳的吸收。采用响应面法（RSM），综合考虑不同粉煤灰（FA）、生物炭(B)掺量及其相互作用的影响，对生物炭-粉煤灰混合料的掺量进行了优化，从而实现了性能提高和碳酸盐矿化的最佳混合料设计。此外，还研究了不同晶型碳酸钙对矿化的影响。实验结果表明，生物炭对高钙粉煤灰砂浆进行加速碳化处理，可使生物炭的有效利用率提高到5%，提高砂浆的力学性能和固co2能力。然而，在正常的养护条件下，观察到生物炭的最佳用量<1%。这是一种很有前途的方法，可以利用废料，减少混合设计中的水泥含量，同时还可以将50%的环境二氧化碳永久储存在胶凝基质中。与未碳化水泥砂浆相比，碳化生物炭-粉煤灰水泥复合材料在第7天和第28天的断裂强度和弹性模量显著提高。本研究表明，生物炭和粉煤灰协同结合在开发低碳、可持续的水泥建筑材料方面具有优势，这些材料有可能在未来将建筑结构转变为碳汇。
The novelty of this study is to find out the optimum amount of biochar and high calcium fly ash to improve mechanical performance and promote CO2uptake in cement mortar. The potential of biochar-fly ash mixes was optimized using response surface methodology (RSM) considering the influence of different amounts of fly ash (FA), biochar (B), and their interactions to achieve the optimal mix design with improved performance and carbonate mineralization. Additionally, the effect on the mineralization of different polymorphs of calcium carbonate was also investigated. The experimental results indicate that the accelerated carbonation of high calcium fly ash mortar enriched with biochar enables the effective utilization of biochar up to 5% for enhancing both the mechanical properties and CO2sequestration. However, under normal curing conditions, it was observed that the optimal amount of biochar that can be used is <1%. This is a promising approach in terms of utilizing waste material and reducing cement content in the mix design together with the additional benefit of storing 50% of ambient CO2permanently in the cementitious matrix. Carbonation of biochar-fly ash cement composite substantially improves fracture strength, and modulus of elasticity compared to uncarbonated cement mortar at 7 and 28 days. The present study demonstrates the advantages of synergistically combining biochar and fly ash in the development of low-carbon, sustainable cementitious building materials that have the potential to transform building structures into carbon sinks in the future.