Papers by Keyword: Frost Resistance

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Authors: Xiao Ke Li, Wen Hui Song, Chang Yong Li
Abstract: Compared with ordinay concrete, weight of lightweight aggregate concrete could be lower 20%-40% under same bearing capacity. Mixed with some given steel fibers in it, crack resistance and flexural strength will be improved. Once lightweight aggregate concrete mixed with steel fibers meets the requirements of frost resistance, it could be applied to most civil engineerings in a cold area. In this paper, the frost resistance mechanism of steel fiber reinforced lightweight aggregate concrete is introduced. The research status of frost resistance of steel fiber reinforced lightweight aggregate concrete is reviewed including the effects of water cement ratio, aggregate, mineral admixture and amount of fiber, frost resistance experimatal methods and engineering applications etc. Some further researches are prospected.
Authors: Chao Zhao, Jun Zhao Gao
Abstract: By scanning the images of bubble structure made through a microscope and measuring characteristic parameters of bubble structure, the paper analyzes the influence of concrete, which is made of different proportion of mineral admixture, on bubble formation and its stability and the influence of bubble characteristics on frost resistance of concrete so as to promote people’s understanding of air-entraining agent application technology.
Authors: Rudolf Hela, Martin Ťažký, Václav Vachuška, Tomáš Ťažký
Abstract: Conventional high temperature fly ash has been used for manufacturing of construction materials, concrete in particular, for quite a long time. Fluidized bed combustion fly ash, however, has little use in this area, mainly for its chemical composition and morphology. Current efforts are directed towards the development of new technological processes and building materials that would allow the use of this industrial waste and its qualities. One possible way of fluidized bed combustion fly ash’s utilizing in construction industry is the production of cold balled lightweight aggregate. Production of this material is economically advantageous and enables processing of large volumes of raw materials. This paper describes possibilities of using this aggregate for production of lightweight concrete of lower compressive strength classes and consequent testing of durability and resistance to various types of aggressive environment and cyclical freezing and thawing. Physico-mechanical properties and microscopic defects were also studied
Authors: Ondřej Zobal, Pavel Padevět, Tomáš Plachy
Abstract: This paper is dedicated to the use of fly ash in cement and concrete. Using fly ash in cement and concrete has ecological and economic benefits. However, it is important to correctly apply the fly ash. If the substitution is close to 50% or more by weight of clinker (HVFAC - High-Volume Fly Ash Concrete), it is necessary to monitor the material and mechanical properties. This paper describes an analysis of a frost resistance of a cement paste with fly ash. The destructive and non-destructive tests were carried out.
Authors: Ondřej Zobal, Pavel Reiterman, Tomáš Plachý, Zdeněk Bittnar
Abstract: The paper focuses on some properties of concrete with fly ash after 55 years in operation. Among other things this topic refers to still current issue of sustainable development. In this case, it is saving of cement by using of substitution of fly ash. Another researched topic in the paper is the durability of structures and building materials. For obtaining important data, samples of concrete were extracted from the body of the dam Orlík, which has been in operation since 1961 and fly ash was used in a mixture. The results of the measurement of carbonation and frost resistance of concrete with fly ash addition are presented and analyzed in this paper.
Authors: Tomáš Melichar, Jiří Bydžovský, Vit Černý
Abstract: The article deals with the study of the effect of modification of composition of cement-bonded particleboards on their frost resistance. Powder waste from the line for production of cement-bonded particleboards was used for preparation of test units. Conditions of storage under alternating freezing and defrosting in combination with effect of water were specifically created. Subsequently, the fundamental physical-mechanical parameters were assessed.
Authors: Yu Jie Jin, Li Guang Xiao, Feng Luo
Abstract: Owing to the disadvantages of traditional mortar with poor antifreeze property,low adhesive strength and short durability in the cold region of China, the facing tiles often fall off and lead to the lost of decorative effects and protective effects. In this article,a new type of mortar for exterior wall facing tile,polymer cement mortar modified by polymer, is introduced. The advantages of the new mortar are: (l) Better frost resistance,which is reflected by stability after one hundred cycles of freezing and thawing; (2) Higher adhesive strength (2.0MPa); (3) Better permeability resistance and longer durability. It is believed that an ideal building mortar for the resistance of frost damage and suitable for exterior wall facing tile.
Authors: Zheng Mao Ye, Liancong Zheng, Yong Zhang, Xin Cheng
Abstract: Frost Resistance of rapid hardening sulphoaluminate cement was modified with redispersible powders. Frost resistance and strength of sulphoaluminate cement mortar were tested. With the help of SEM and mercury porosimetry, the morphology of the hydrates and the micro-structure of the mortar were observed. The frost resistance mechanism of redispersible powders in the mortar is analyzed. The results show that the frost resistance of sulphoaluminate cement mortar could be improved significantly by mixing redispersible powders. The optimal content of redispersible powders is 0.9%.
Authors: Liang Feng Dong, Shi Ping Zhang
Abstract: This paper presents the results on the influence of steel fiber on the performance of concrete materials. The performance of steel fiber reinforced concrete was studied through mechanical testing, frost resistance, carbonation and impermeability testing. Experimental results showed that steel fibers can improve compressive and flexural strengths, and especially can significantly improve flexural strength. Frost resistance can also be improved, and the higher the volume of steel fibers added, the more the freeze-thaw cycles that concrete could resist. Furthermore, steel fiber can not only slow down the carbonation rate indirectly, but also improve the impermeability of concrete, and impermeability enhanced with the increase of steel fiber.
Authors: Shi Ping Zhang, Xiang Dong
Abstract: This paper presents the results of testing performed to evaluate the influence of steel fiber on the performance of concrete materials. The performance of concrete materials was studied through frost resistance, carbonation testing and restraint cracking testing. Experimental results show that the steel fibers can improve the frost resistance and carbonation of concrete, compared with plain concrete. Steel fibers can also reduce cracking, and improve the cracking resistance of concrete materials.
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