International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 03 | Mar 2025
p-ISSN: 2395-0072
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Study on Compressive Strength of Cement Mortar Containing Rice Husk Ash and Silica Fume under Freeze-Thaw Cycles Haoyi Ren1, Shilong Wang2 1,2School of Civil Engineering and Architecture, Anhui University of Science and Technology, Anhui, China
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Abstract - To investigate the influence of rice husk ash
decomposition of rice husks, serious environmental pollution has arisen. Researchers from around the world have actively discussed and conducted experimental studies on the utilization of rice husk ash. Countries, such as the United States, the former Soviet Union, Japan, and India, began to study its properties at an early stage. China has carried out more systematic research since the 1980s. Through research, it has been found that the chemical composition of rice husks calcined by high temperature is similar to silica fume, containing a large amount of highly active silica. Incorporating it into cement-based composites can significantly improve the mechanical properties [8], workability [9], and durability [10].
(RHA) on the compressive strength and freeze-thaw resistance of cement mortar, the WAW-1000 universal testing machine was conducted to analyze the compressive mechanical properties of cement mortar specimens under varying RHA replacement ratios and freeze-thaw cycles. Scanning Electron Microscope (SEM) was further used to analyze the changes in the microstructure of cement mortar. The results demonstrated that the compressive strength of cement mortar increased with the increased of RHA replacement ratios. After curing for 28 days, the compressive strength of specimens with 5% RHA replacement for silica fume increased by 70.4% compared to the control group. With an increasing number of freezethaw cycles, the rate of compressive strength reduction in cement mortar containing rice husk ash and silica fume was significantly slower than the control group. SEM microstructural analysis revealed that RHA effectively mitigates damage induced by freeze-thaw cycles, thereby improving the durability of cement mortar.
Therefore, this study uses the rice husk ash calcined at a controlled temperature of 600°C to replaces part of the silica fume, investigating its influence on the compressive mechanical properties and frost resistance of cement mortar. The results will provide a reference for the widespread application of rice husk ash in concrete.
1.1 Raw Materials
Key Words: Rice husk ash; Cement mortar; Freeze-thaw cycles; Freeze-thaw resistance; Compressive strength
In this study, the rice husk is calcined into ash at a controlled temperature of 600°C. The grade of cement is ordinary Portland cement of 42.5. The fineness modulus of the sand is 1.69, and the silica content of the silica fume is 96%. The mixing and curing water used are distilled water.
1. INTRODUCTION The cold regions are widely distributed in the northern of China [1]. With the shift of China's social economy and infrastructure construction towards the western region, the development of cold region engineering has progressed rapidly. However, buildings in cold regions are inevitably affected by freeze-thaw cycles [2], which can cause significant harm to the projects. According to relevant data statistics [3], the cement industry has a large energy consumption, leading to the greenhouse gas emissions account for 8% to 10% of the global total. At the same time, natural resources are becoming scarcer, and the use of industrial waste in cement concrete is becoming more common [4]. For example, the use of slag and fly ash in concrete can not only reduce resource waste and the pollution caused by waste accumulation, but also promote the development of new low-carbon and environmentally friendly building materials, generating excellent economic and environmental benefits [5-6].
1.2 Specimen Preparation Firstly, Put the rice husks into the hydrochloric acid solution, stir thoroughly, and soak for 1 hour. Then, repeatedly rinse the acid-soaked rice husks with distilled water until the rinsing solution is in a neutral state. Next, put the rinsed rice husks into an oven for drying. Subsequently, put the dried rice husks into a muffle furnace and calcine them at a stability temperature of 600°C for 3 hours. Finally, put the calcined rice husks into an ice-water mixture at 0°C for rapid cooling. After cooling, grind them into a fine powder and sieve it through a 180-mesh sieve. The mix proportion in this study is based on the research findings from existing references [11-13]. The materials mix proportions (kg/m³) are as follows: cement: sand: water = 330:1210:160.
China, the world's largest rice-growing country, produces about 40 million tons of rice husks every year [7]. However, due to high hardness and difficult
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