| LI Shuang-xin,GAO Xiao-jian.Effect of Nano Al2O3 and MgO on Abrasion Resistance and Mechanism of Ultra-high Performance Concrete[J],47(10):123-130 |
| Effect of Nano Al2O3 and MgO on Abrasion Resistance and Mechanism of Ultra-high Performance Concrete |
| Received:March 08, 2018 Revised:October 20, 2018 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2018.10.016 |
| KeyWord:ultra-high performance concrete nano Al2O3 nano MgO abrasion resistance microstructure cement hydration calcium silicate hydrate gel |
| Author | Institution |
| LI Shuang-xin |
a.School of Civil Engineering, b.Key Laboratory for Structural Engineering Catastrophe and Control of the Ministry of Education, Harbin Institute of Technology, Harbin , China |
| GAO Xiao-jian |
a.School of Civil Engineering, b.Key Laboratory for Structural Engineering Catastrophe and Control of the Ministry of Education, Harbin Institute of Technology, Harbin , China |
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| Abstract: |
| The works aims to increase the strength of concrete to improve the abrasion resistance. In the perspective of material preparation in this work, nano materials are used to improve the strength of ultra-high performance concrete and then increase the abrasion resistance. Nano Al2O3 and MgO were added into UHPC in the weight percentages of cement (0.05%, 0.1%, 0.15%, 0.2% and 1%) to test strength and abrasion resistance for different periods. Typical samples were selected to be analyzed for 29Si and 27Al by NMR and XRD and studied for internal structure to provide theoretical basis for effect mechanism of nano materials on UHPC strength and abrasion resistance. The UHPC mixed with nano MgO had higher strength and better abrasion resistance than plain samples and samples with nano Al2O3. When the admixture dosage reached 0.35% (Mg-2), compressive and flexural strength for 7 d was 1.1 times higher than that of plain samples and the wear reduced by 10%. However, different nano MgO influenced the properties of UHPC to the different extents. From the microstructural characterization, nano MgO increased the hydration process of cement, generated more hydration products and resulted in a denser microstructure. However, nano MgO enhanced the formation of hydrotalcite at the same time. As the amount of nano MgO increased, the production of hydrotalcite also increased, but decreased the structure compact. Abrasion resistance of nano UHPC is proportional to compressive strength. The addition of MgO promotes the hydration process, increases the compact of the microstructure of UHPC and then consequently increases the strength and abrasion resistance. However, over dosage can result in the formation of hydrotalcite in the outer hydration area, which is an adverse factor to increase the compressive strength and abrasion resistance. According to this work, the suitable addition is 0.35%. |
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