| Cementitious capillary crystalline waterproofing material (CCCW) is composed of ordinary Portland cement, quart sand, etc. It is of rigid waterproof material that incorporates active chemical substances. When it is mixed with water and brushed on the surface of concrete, the active chemicals on the carrier of water could penetrate inside of concrete through the poresand cracks and response with the material inside of concrete. At the same time, these chemicals could promote the further hydration of the unhydrated cement and generate the crystalline solid to fill into the the pore, cracks and other defects, so as to effectively improve the compactness of concrete and improve the performance of concrete. In recent years, cementitious capillary crystalline waterproofing material were gradually applied in waterproof of building construction, underground engineering and and bridge engineering, etc, and the related research was mainly focused on experimental research about impermeability of concrete. Howerver, there are still different opinions on the application of concrete reinforcement and repair, and the study on mechanical properties of concrete with cementitious capillary crystalline waterproofing material is relatively few. Against this background, the low-strength concrete and concrete after high temperature are the test objects in this paper, which to study the effect of cementitious capillary crystalline waterproofing material on the rehabilitation or strengthening of concrete.In this experiment, the cementitious capillary crystalline waterproofing material adopted XYPEX concentrate, and a total of 84 concrete cylinders with a diameter of 150mm and a height of 300mm were designed.50 cylindrical specimens were used to study the effect of low strength concrete reinforced repair, the main parameters involved in the test included concrete strength grade (C15.C25). curing period (15d, 30d,45d,60d), whether to brush XYPEX concentrate, etc.34 cylindrical specimens were used to study the effect of concrete after high tempreture reinforced repair, the main parameters involved in the test included high temperature (300?,600?), cooling mode (natural cooling, water cooling), whether to brush XYPEX concentrate, etc. In assigned time, compression test and the SEM scanning electron microscope observation and analysis of the concrete with painted XYPEX concentrate were carried out to study the effect of cementitious capillary crystalline waterproofing material on the mechanical properties and microstructure of concrete. The main conclusions are made as follows:(1) For low strength concrete, the compressive strength of concrete increased with the increase of curing time with painted XYPEX concentrate, and the growth rate was larger than that not brushing. For the concrete specimens after high temperature, that painted XYPEX concentrate could improve the compressive strength in the same condition, and reduced the depth of neutral layer and the peak strain, played a role in improving the mechanical properties of concrete.(2) Both low strength concrete and high temperature concrete, XYPEX concentrate could produce the insoluble crystal by permeability crystallization to fill in the interior of the concrete and played the role of densifying the concrete.(3) The relative content of Na elements in the different depth of coating was tested by energy spectrometer, which to deduce the penetration depth of XYPEX concentrate. The test results show that the penetration depth was more than 20mm in the other working conditions except that penetration depth of C25 concrete was 15-20mm.Finally, this paper briefly introduces several construction methods of the cementitious capillary crystalline waterproofing material at present. In combination with some problems found during the course of the study, some suggestions and precautions are put forward. The above research results can guide the application of the cementitious capillary crystalline waterproofing material for rehabilitating or strengthening concrete in practice. |
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