ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty


EFFECT OF REHYDRATION OF UNHYDRATED CEMENT ON ULTRA-HIGH PERFORMANCE CONCRETE AFTER HEAT CURING
 
Wu Xiong 1,2, Luo Yaoling 2, Yang Wen 2, Gao Yuxin 2, Bi Yao 2, Xie Yuhao 2
 
1 School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
2 China West Construction Academy of Building Materials, Chengdu, 610015, China.

Keywords: UHPC, Unhydrated cement, Moisture susceptibility, Pore structure
 

Mechanical performance testing, X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) were used to study the effect of rehydration of unhydrated cement on ultra-high performance concrete (UHPC) under contact moisture and to isolate the moisture environments after different curing temperatures. The results indicated that the unhydrated cement particles can continuously hydrate when in contact with moisture and reduce the porosity, especially the 10∼100 nm pores, and continuously improve the late strength of UHPC at 20 °C and 90 °C under a contact moisture environment. Contact with moisture will significantly increase the porosity and the 10∼100 nm pores of the specimen, thereby leading to severe strength shrinkage and causing moisture susceptibility problems to the UHPC, while the isolated moisture also causes a slight reduction in the strength after curing at 250 °C. Contact with moisture can cause more severe strength shrinkage when the curing temperature is 250 °C.


doi: 10.13168/cs.2021.0032
 
 
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