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| Effect of Curing Methods on Hydration Processes and Mechanical Property of Track Slab Concrete |
| LI Shuming, XIE Yongjiang, ZHENG Xingguo, LIU Jing, WANG Yuehua, WENG Zhicai |
| Railway Engineering Research Institute, China Academy of Railway Sciences Corporation Limited, Beijing 100081, China |
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Abstract Research purposes: Steam curing is a common curing method of track slab concrete, but high temperature steam curing is easy to cause internal damage of hydration products. In order to study the suitable accelerated curing method of track slab concrete, the effect of different curing methods on cement hydration and mechanical properties was explored. The temperature rise, strain, compressive strength and hydration process of track slab concrete were measured and the micro morphology of hydration product was observed under four curing methods, such as 45 ℃ steam curing, 45 ℃ dry heat curing, heat preservation curing and nature curing.
Research conclusions:(1) The temperature rise rate was quicker under steam curing and dry heat curing, the early compressive strength was improved significantly, thermal expansion deformation was exhibited at 0~7 h and shrinkage deformation was discovered after 7 h. Meanwhile, there were more hydration products at early stage, such as Ca(OH)2 and AFt, and more micro cracks at later stage, which made the later strength reduced. (2) The temperature rise rate of concrete under heat preservation curing were lower than the concrete under steam curing and dry heat curing, which could promote the early compressive strength of concrete. The demoulding strength of track slab concrete can meet requirement after curing 18 h. The concrete mainly showed shrinkage deformation under heat preservation curing, fewer defects of hydration products and stable strength in the later stage. (3) The heat preservation curing can be used as an accelerated curing method for track slab concrete.
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Received: 17 February 2022
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2023, Vol. 40 
