Alabduljabbar Hisham, Huseien Ghasan Fahim, Sam Abdul Rahman Mohd, Alyouef Rayed, Algaifi Hassan Amer, Alaskar Abdulaziz
Department of Civil Engineering, College of Engineering, Prince Sattam bin Abdulaziz University, Alkharj 11942, Saudi Arabia.
Construction Research Centre, Institute for Smart Infrastructure and Innovative Construction, School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia.
Materials (Basel). 2020 Dec 2;13(23):5490. doi: 10.3390/ma13235490.
Alkali activated concretes have emerged as a prospective alternative to conventional concrete wherein diverse waste materials have been converted as valuable spin-offs. This paper presents a wide experimental study on the sustainability of employing waste sawdust as a fine/coarse aggregate replacement incorporating fly ash (FA) and granulated blast furnace slag (GBFS) to make high-performance cement-free lightweight concretes. Waste sawdust was replaced with aggregate at 0, 25, 50, 75, and 100 vol% incorporating alkali binder, including 70% FA and 30% GBFS. The blend was activated using a low sodium hydroxide concentration (2 M). The acoustic, thermal, and predicted engineering properties of concretes were evaluated, and the life cycle of various mixtures were calculated to investigate the sustainability of concrete. Besides this, by using the available experimental test database, an optimized Artificial Neural Network (ANN) was developed to estimate the mechanical properties of the designed alkali-activated mortar mixes depending on each sawdust volume percentage. Based on the findings, it was found that the sound absorption and reduction in thermal conductivity were enhanced with increasing sawdust contents. The compressive strengths of the specimens were found to be influenced by the sawdust content and the strength dropped from 65 to 48 MPa with the corresponding increase in the sawdust levels from 0% up to 100%. The results also showed that the emissions of carbon dioxide, energy utilization, and outlay tended to drop with an increase in the amount of sawdust and show more the lightweight concrete to be more sustainable for construction applications.
碱激活混凝土已成为传统混凝土的一种潜在替代品，其中各种废料已被转化为有价值的副产品。本文对使用废锯末作为细/粗骨料替代品、掺入粉煤灰（FA）和粒化高炉矿渣（GBFS）以制备高性能无水泥轻质混凝土的可持续性进行了广泛的实验研究。废锯末以0、25、50、75和100体积%的比例替代骨料，并掺入碱粘结剂，其中包括70%的FA和30%的GBFS。使用低浓度氢氧化钠（2M）对混合物进行激活。评估了混凝土的声学、热学和预测的工程性能，并计算了各种混合物的生命周期，以研究混凝土的可持续性。除此之外，利用现有的实验测试数据库，开发了一种优化的人工神经网络（ANN），以根据每个锯末体积百分比估计设计的碱激活砂浆混合物的力学性能。基于这些发现，发现随着锯末含量的增加，吸声和热导率降低得到增强。发现试件的抗压强度受锯末含量的影响，随着锯末含量从0%相应增加到100%，强度从65MPa降至48MPa。结果还表明，随着锯末用量的增加，二氧化碳排放量、能源利用率和费用趋于下降，这表明轻质混凝土在建筑应用中更具可持续性。
