| INORGANIC MATERIALS AND CERAMIC MATRIX COMPOSITES |
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| The Mechanism of Expansion Stress Produced by Hydration of Compacted CaSO4·2H2O-C3A |
| WANG Weibiao, MO Liwu, DENG Min
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| College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 |
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Abstract The expansive stress produced by compacted CaSO4·2H2O-C3A soaked in water, Ca(OH)2-saturated solution and 1 mol/L NaOH solution was measured by a self-designed device, and the swelling expansive stress of the ettringite hydrated by CaSO4·2H2O-C3A compact.The results show thatettringite was the only product in compacts immersed in water and solutions. The maximum expansive stress produced by the compacts cured in 40 ℃ water, Ca(OH)2-saturated solution and 1 mol/L NaOH solution was 23.9 MPa, 27.3 MPa and 26.4 MPa, respectively. Lower expansive stress of the compact hydrated in water than that hydrated in Ca(OH)2-saturated solution and 1mol/L NaOH solution seems to indicate that both Ca(OH)2-saturated and NaOH solution may promote the expansive stress of ettringite formation. However, the maximum expansion stresses due to the swelling of the generated ettringitein compacts cured in 40 ℃ water, 1 mol/L NaOH solution and Ca(OH)2-satura-ted solution only were about 1.23 MPa, 1.27 MPa and 1.26 MPa, respectively. The swelling pressure is much lower than the expansive stress generated by hydration of CaSO4·2H2O-C3A compacts. This indicates that crystallization pressure of the ettringitewas the main reason of expansion stress and the swelling stress of ettringite had little contribution.
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Published: 28 April 2019
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| Fund:This work was financially supported by the National Natural Science Foundation of China (51461135003). |
| About author:: Weibiao Wang, received his M.S. degree in June 2018 from Nanjing Tech University in engineering, focusing on the research of cementconcrete material.; Min Deng, doctoral supervisor,Nanjing Tech University. Focusing on the research of concrete durability, MgO expansive agent and industrial solid waste. |
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2019, Vol. 33 
