Bui Quoc-Bao, Nguyen Tan-Phat, Schwede Dirk
Sustainable Developments in Civil Engineering Research Group, Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
Energy and Building Services, Department of Architecture and Civil Engineering, Technische Hochschule Lübeck, Lübeck, Germany.
Sci Rep. 2023 Dec 21;13(1):22905. doi: 10.1038/s41598-023-50103-6.
The construction industry is one of the sectors which have significant impacts on the environment. The research on sustainable materials is a demand of society. This paper presents an investigation on the use of fly ash (FA) geopolymer binder for the production of unburnt bricks. First, an optimisation process for the ratio of alkaline activator solution (AAS) and FA was performed. The blocks were obtained by compressing the materials in a mould by hand, similar to the traditional technique of the adobes. Different ratios of AAS in the blocks were investigated: 6%, 8%, 12% and 20% by mass, respectively. Two curing temperatures were tested: ambient temperature and at 60 °C. Then, different properties of the blocks were determined: flexural tensile strength, compressive strengths (in the quasi-dry state and in the saturated state), water absorption. The techniques of Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM) were also used for the analyses of the results obtained. The results showed that the blocks with 20% AAS had highest compressive strengths with an average of 24 MPa at 28 days, while the recommended AAS amount for both technical and economical points of view was 8%, with a mean compressive strength of 13 MPa at 28 days. The ratio between the saturated compressive strength on the quasi-dry compressive strength was higher than 0.5, which satisfied the current exigencies from the standards. These exploratory results are important for practice applications of this type of blocks.
建筑业是对环境有重大影响的行业之一。对可持续材料的研究是社会的需求。本文介绍了关于使用粉煤灰（FA）地质聚合物粘结剂生产免烧砖的调查。首先，对碱性活化剂溶液（AAS）与FA的比例进行了优化过程。这些砖块是通过手工在模具中压制材料获得的，类似于土坯的传统技术。研究了砖块中不同比例的AAS：分别为质量的6%、8%、12%和20%。测试了两种养护温度：环境温度和60°C。然后，测定了砖块的不同性能：弯曲抗拉强度、抗压强度（在准干燥状态和饱和状态下）、吸水率。还使用了傅里叶变换红外（FTIR）和扫描电子显微镜（SEM）技术对所得结果进行分析。结果表明，AAS含量为20%的砖块在28天时具有最高的抗压强度，平均为24MPa，而从技术和经济角度来看，推荐的AAS用量为8%，28天时的平均抗压强度为13MPa。饱和抗压强度与准干燥抗压强度之比高于0.5，满足了当前标准的要求。这些探索性结果对于这类砖块的实际应用具有重要意义。
