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Effects of Curing Methods on the Permeability and Mechanism of Cover Concrete
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作者 Wang Hao Baolin Guo +3 位作者 Yongzhi Guo Ruishuang Jiang Fangli Zhao Baomin Wang 《Journal of Building Material Science》 2023年第1期20-31,共12页
Curing methods are one of the most important factors in determining the quality and compactness of cover concrete.The effect of curing methods on the water absorption and sorptivity coefficient of cover concrete with ... Curing methods are one of the most important factors in determining the quality and compactness of cover concrete.The effect of curing methods on the water absorption and sorptivity coefficient of cover concrete with the substitution ratio of fly ash(FA)and ground granulated blast slag(GGBS)for cement between 30 wt%and 40 wt%was studied by capillary water absorption test.The vacuum saturation test and mercury intrusion test were employed to characterize these differences in the pore structure of cover concrete under different curing methods.With further analysis of the compactness of microstructure by SEM,the mechanism of the impact of curing methods on the permeability of cover concrete was revealed.The results obtained indicate that the effect of curing methods on the water absorption,sorptivity coefficient and porosity of cover concrete shows the trend of natural curing>cover curing>water curing>standard curing.It is also shown that reasonable curing is advantageous to reduce the porosity and permeability of cover concrete.In natural curing conditions,the appearance of porosity increasing and pore structure coarsening is more critical for covering concrete with mineral admixtures than for pure cement concrete.Therefore,the permeability of cover concrete with mineral admixtures is more sensitive to the early-age curing methods. 展开更多
关键词 Curing methods cover concrete PERMEABILITY Capillary water absorption POROSITY
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Comparison study of durability design for concrete bridges:Chinese-code and Eurocode 被引量:2
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作者 仝腾 刘钊 《Journal of Southeast University(English Edition)》 EI CAS 2011年第4期436-440,共5页
Differences and similarities of durability design for concrete bridges in Chinese-code and Eurocode are identified and discussed. Exposure environment classes and regulations of the minimum concrete cover and strength... Differences and similarities of durability design for concrete bridges in Chinese-code and Eurocode are identified and discussed. Exposure environment classes and regulations of the minimum concrete cover and strength of the two codes are compared and analyzed. Numerical calculations for predicting the durable life of bridges related to carbonization and chlorides corrosion (marine and de-icing) are conducted. The results show that provisions in the two codes can satisfy the durability requirements under carbonization whereas they cannot guarantee the durability for bridges in spray and splash zones. Enhancing the waterproof capacity and reducing the frequent use of de-icing agents are vital to improving the bridge durability. Some recommendations for upgrading the durability are also included. 展开更多
关键词 BRIDGE DURABILITY CARBONIZATION chloride corrosion concrete cover
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Size effect of confined concrete subjected to axial compression 被引量:4
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作者 李振宝 宋佳 +1 位作者 杜修力 杨修广 《Journal of Central South University》 SCIE EI CAS 2014年第3期1217-1226,共10页
In order to investigate the size effect and other effects on the stress-strain relationship of confined concrete, 42 specimens with different sizes and section shapes were placed under axial compression loading. Effec... In order to investigate the size effect and other effects on the stress-strain relationship of confined concrete, 42 specimens with different sizes and section shapes were placed under axial compression loading. Effects of key parameters such as size of specimens, tie configuration, transverse reinforcement ratio, and concrete cover were studied. The results show that for specimens with the same configuration and the same volumetric ratio of the transverse reinforcement, along with the increasing specimen size, the peak stress, peak strain and deformation of the post-peak show a down trend, however, the volumetric ratio of the transverse reinforcement is lowered, the decreasing of the peak stress is accelerated, but the decreasing of the deformation is slow down. For specimens with the same volumetric ratio but different configurations of transverse reinforcement, though the transverse reinforcement configuration becomes more complicated, the peak stress of the large size specimen does not improve more than that of the small size. However, the deformation occurs before the stress declines to 85% of peak stress, and the improvement with the grid pattern tie configuration is much greater due to size effect. 展开更多
关键词 confined concrete mechanical property size effect configuration type of transverse reinforcement volumetric ratio oftransverse reinforcement concrete cover
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Prediction of the Residual Strength for Durability Failure of Concrete Structure in Acidic Environments 被引量:2
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作者 李北星 CAI Laohu +1 位作者 WANG Kai ZHANG Yaming 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第2期340-344,共5页
According to the results of accelerated tests of acidification corrosion depth and compressive strength of concretes subjected to sulfuric acid environments,the acidification depth laws of concretes were predicted bas... According to the results of accelerated tests of acidification corrosion depth and compressive strength of concretes subjected to sulfuric acid environments,the acidification depth laws of concretes were predicted based on the grey system theory.Thus,the remaining compressive strength was calculated when the acidification depth reached the protection layer thickness of concrete structures,which indicates that the limit state of durability failure can be defined based on strength degradation,and the calculation process was illustrated by an example.The calculated results show that the remaining compressive strength values in the durability failure limit state for the concrete structures exposed to p H=2 and 3 sulfuric acid water environments and wet-dry cyclic sulfuric acid environment with p H=2 are 74%,72%,and 80% of initialstrength,respectively.The method provides references for the durability evaluation of concrete structure design under the acidic environments. 展开更多
关键词 concrete structure acidification durability evaluation strength degradation concrete cover thickness
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A Calculation Model for Corrosion Cracking in RC Structures 被引量:8
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作者 徐港 卫军 +1 位作者 张克强 周锡武 《Journal of China University of Geosciences》 SCIE CSCD 2007年第1期85-89,共5页
A novel calculation model is proposed aiming at the problem of concrete cover cracking induced by reinforcement corrosion. In this article, the relationship between the corrosion depth of the bar and the thickness of ... A novel calculation model is proposed aiming at the problem of concrete cover cracking induced by reinforcement corrosion. In this article, the relationship between the corrosion depth of the bar and the thickness of the rust layer is established. By deducing the radial displacement expression of concrete, the formula for corrosion depth and corrosion pressure before cracking is proposed. The crack depth of cover in accordance with the maximum corrosion pressure is deduced; furthermore, the corrosion depth and corrosion pressure at the cracking time are obtained. Finally, the theoretical model is validated by several experiments, and the calculated values agree well with the experiment results. 展开更多
关键词 concrete cover REINFORCEMENT corrosion products corrosion pressure
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Study on Impact of Embodied Energy and CO2 Emissions for Prolongation of Building Life Time: Case Study in Japan
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作者 Keizo Yokoyama Makoto Yamamoto +2 位作者 Noriyoshi Yokoo Tatsuo Oka Takao Sawachi 《Journal of Civil Engineering and Architecture》 2015年第3期274-282,共9页
In this study, we looked at a method quantifying EEC (embodied energy and CO2) and the effect when we prolonged the building life time particularly through the durable improvement of the structure. Increasing the co... In this study, we looked at a method quantifying EEC (embodied energy and CO2) and the effect when we prolonged the building life time particularly through the durable improvement of the structure. Increasing the covering thickness of concrete for reinforcing bars and the earthquake-resistant strength are methods to increase the durability of the structure. The calculation method to obtain the quantity of concrete and reinforcing bars is provided. The EEC increase is evaluated from the 2005 input-output table in Japan. These results show that EE (embodied energy) in the construction phase is increased by 11% to 20% and EC (embodied CO2) 17% to 32%. However, annual EE is reduced 66% to 72% and EC 70% to 79%, 展开更多
关键词 covering thickness of concrete earthquake-resistant strength I-O (input-ouput) table embodied energy/CO2
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