Abstract
This article studies the efficiency of sand powder as a supplementary cementitious material (SCM) in improving the sulfuric acid resistance of concrete incorporated with high CaO fly ash. Besides, the effects of sand powder on compressive strength development, mitigation of carbon dioxide emission, and cost-effectiveness are addressed. Paste mixtures with W/B ratios of 0.25 and 0.40 were used in this study for the performances of sulfuric acid resistance and long-term compressive strength development. The test results indicated that sand powder could reduce the weight loss of the tested paste specimens in sulfuric acid solution with a pH of 1, compared to the control specimens, especially for the specimens incorporated with high CaO fly ash. The sand powder addition could also increase the compressive strength of cement pastes at the age of 90 days by 26.27% and 43.80% for W/B ratios of 0.25 and 0.40, respectively. The use of sand powder in the evaluated concrete mixture could also reduce CO2 emission by 23.23% and lower the cost of the mixtures by 8.05%, compared to the control mixture. The addition of sand powder could significantly increase the sulfuric acid resistance, compressive strength, and economic benefits and reduce the CO2 emission of high CaO fly ash-cement-based materials.
Highlights
Concrete is one of the most widely used construction materials
Mixtures in which cement was partially replaced by the high calcium oxide (CaO) Mae Moh fly ash, by low CaO BLCP fly ash, and by combined high CaO fly ash with sand powder were studied and compared for the acid resistance, cost, and CO2 emissions. e results of this study will be useful in the future for mix proportion optimization of acid-resisting concrete with the use of the most typical fly ash type and sand powder
Compressive strength measurements of the specimens were carried out at the ages of 3, 7, 28, and 90 days. e compressive strength of a mixture was calculated from the average of 3 tested specimens. e test results are shown in Figure 4. e compressive strengths of the mixtures with a W/B of 0.25 and 0.40 show a similar tendency
Summary
Concrete is one of the most widely used construction materials. It offers satisfactory strength for constructed structures. e cost and the durability of concrete in aggressive environments should be considered. Is material could be used in combination with the high CaO Mae Moh fly ash to improve the acid resistance, reduce the mixture cost, and reduce the CO2 emission of the concrete mixtures. Many researchers studied the use of cement-replacing materials (CRMs) with high SiO2 contents such as silica fume, which can improve both the strength and acid resistance of concrete [6]. E purpose of this research is to study the possibility of using sand powder to improve the acid resistance of concrete incorporated with high CaO Mae Moh fly ash. Mixtures in which cement was partially replaced by the high CaO Mae Moh fly ash, by low CaO BLCP fly ash, and by combined high CaO fly ash with sand powder were studied and compared for the acid resistance, cost, and CO2 emissions. Mixtures in which cement was partially replaced by the high CaO Mae Moh fly ash, by low CaO BLCP fly ash, and by combined high CaO fly ash with sand powder were studied and compared for the acid resistance, cost, and CO2 emissions. e results of this study will be useful in the future for mix proportion optimization of acid-resisting concrete with the use of the most typical fly ash type (high CaO fly ash) and sand powder
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