Papers by Author: Xiao Yan Zhang

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Authors: Na Liang, Xiao Yan Zhang, Feng Lan Li
Abstract: Experiments were carried out to investigate such basic properties as workability and strength of masonry cement mortar affected by mass content of polypropylene fiber. The results show that proper mass content of polypropylene fiber is helpful for effectively adjusting consistency and layering to bring better workability of fresh mortar, the relative higher bending strength of mortar can be got by admixing reasonable mass content of polypropylene fiber while slight improved compressive strength reaches. The relationships of water to cement ratio and mass content of polypropylene fiber in affecting these basic properties of masonry mortar are analyzed, which can be as reference for selecting optimum water to binder ratio and mass content of polypropylene fiber in practices.
986
Authors: Na Liang, Xiao Yan Zhang, Li Sun, Feng Lan Li
Abstract: Experiments were carried out to investigate the dry-shrinkage of masonry mortar affected by mass content of polypropylene fiber. The results show that proper content of polypropylene fiber is helpful to effectively reduce dry-shrinkage of mortar especially in early age, the reduction relates to water to cement ratio of mortar. Meanwhile, the relationships of water to cement ratio and content of polypropylene fiber in affecting dry-shrinkage of masonry mortar are analyzed, which can be as reference for selecting such optimum values as water to cement ratio and content of polypropylene fiber in practices.
1138
Authors: Xiao Yan Zhang, Xin Xin Ding, Shun Bo Zhao, Zhan Fang Ge
Abstract: Experiments were conducted to study the effects of source rock state and stone powder on freeze-thaw resistance of concrete with proto-machine-made sand, the strength grade of concrete was C50, the source rock states were gravel and crushed stone, the contents of stone powder in sand were 5%, 9% and 13% respectively. The values of relative dynamic elastic modulus and mass of concrete at different freeze-thaw cycle times were measured, the reduction of relative dynamic elastic modulus and mass loss were calculated to evaluate the freeze-thaw resistance of concrete. The results show that freeze-thaw resistances are controlled by the reduction of relative dynamic elastic modulus of concrete, which are good of concrete with proto-machine-made sand of gravel and crushed stone, and increases with the increasing content of stone powder in sand made of gravel. The reasons leading to difference of freeze-thaw resistance of concrete with sand made of gravel and crushed stone are discussed.
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Authors: Xiao Ke Li, Xiao Lu Ma, Xiao Yan Zhang
Abstract: As the needs of fair-faced concrete structures for the ecological environment, this paper studies the mix proportion of fair-faced concrete in C30 strength grade by experiments. 13 concretes were designed and tested considering the water to cement ratio, the cement content, the percent of pulverized fly ash, the sand ratio, the water reducer and the formwork parting agent. The workability of fresh concrete, the compressive strength of hardened concrete at 7d, 28d and 56d, and the apparent quality as well as the surface brightness of concrete were got. The results show that the surface color and brightness of concrete were influenced successively by the cement content, the water to cement ratio, the sand ratio and the percent of pulverized fly ash. The use of formwork lacker may bring concrete into better brightness, while the mix oil may be a good selection considering the cost of parting agent. The suitable mix proportions of C30 concrete for urban bridge are proposed.
383
Authors: Xiao Yan Zhang, Xu Chao Liu, Shun Qun Yang, Li Li Dong
Abstract: Due to the larger workflow, more complex foundation and special structure and with the 8° design seismic intensity, it is necessary to analyze this sedimentation basin in the static and dynamic by 3D finite element method. This paper describes the structural model and the selected parameters for calculation of static and dynamic properties, and states the stress analysis results under the various conditions.
292
Authors: Xiao Yan Zhang, Na Liang
Abstract: The skeleton of concrete is determined by aggregate gradation. This paper studies the permeability and mechanical properties of pervious concrete affected by the aggregate gradation. Eight levels of aggregate gradation were selected, which included the single grain grading, double size grain grading and continuous grading. It is found that by series of tests, compared to the pervious concrete with the single grain grading and double size grain grading, the pervious concrete with continuous grading has low porosity, small permeability coefficient, high cubic compressive strength and similar splitting tensile strength and the flexural strength.
145
Authors: Xiao Yan Zhang, Xiao Lu Ma, Li Hui Jin, Xiao Ke Li
Abstract: To keep the perfect, artistic and natural characteristics of fair-faced concrete, it is necessary realizing its weather fastness. This paper introduces the simulated environment test for weather fastness of fair-faced concrete considering the environmental actions at all seasons such as washing of acid rain, sand blown by the wind, exposure to blazing sunlight, salt-fog, carbonization and freeze-thaw. Test methods for sand blown by the wind, washing of acid rain, slow freeze-thaw and exposure to blazing sunlight were invented. The mass change of concrete were measured, and the surface quality was evaluated by the glossiness, the pixel difference and the variance of pixel difference. The results showed that the mass had a little change under the comprehensive actions. The factors decreasing the surface quality in sequence from serious to slight were the washing of acid rain, the salt-fog, the freeze-thaw and the carbonization. The erosion degree increased with the increasing pH value in rainwater and the increasing density of sulfate-ion in salt-fog solution. The surface of concrete damaged by the long-term freeze-thaw and carbonization. The sand blown by the wind, and the exposure to blazing sunlight had little influence on the surface of concrete.
1150
Authors: Chun Jie Liu, Yang Yang Xu, Xiao Yan Zhang
Abstract: As part of the studies on the durability of concrete with machine-made sand, this paper introduces the test results and the forecast model of time-dependent chloride penetration of this kind of concrete. Three strength grades of concrete C30, C40 and C50, and the contents of stone powder in machine-made sand of 5%, 9% and 13% in mass were considered in the mix proportion of concrete with machine-made sand. The ordinary concrete with natural river sand in the same strength grade was tested at the same time for comparison. The test was conducted for 360 days, the results showed that the effect of the content of stone powder on the chloride penetration of concrete was obvious at early curing time of 7 days, and tended to be lower with the increase of curing time. When the curing time was longer than 90 days, this effect could be neglected, and the resistance to chloride penetration of concrete with machine-made sand was almost equal to or larger than that of ordinary concrete. The decrement of chloride diffusion coefficient varied from sharp to gentle with the curing time, the resistance of concrete to chloride penetration increased with the increase of concrete strength. Meanwhile, to facilitate the calculation in practice, the forecast model of chloride diffusion coefficient of concrete is proposed.
3
Authors: Ren Jiang Li, Zheng Gui Zhu, Xian Hua Yao, Xiao Yan Zhang
Abstract: The effect of different water absorption and texture of fine aggregate on properties of dam concrete is significant. This paper studies the properties of dam concrete made by the same and different kinds of fine aggregates. The results showed that concrete made by fine aggregate with high water absorption have higher degree of hydration, larger workability, lower ultimate tensile strength, compared to concrete made by limestone sand. Concrete made by basalt sand have lower strength, higher dry shrinkage, lower autogenously volume deformation.
174
Authors: Xiao Yan Zhang, Qiu Yan Sun, Feng Lan Li
Abstract: Based on a series tests, the properties of proto-machine-made sand of gravel such as grain feature, fineness modulus, grading, density, void ratio and MB value as well as the fineness distribution of stone powder were studied, the influences of content of stone powder on these properties of sand and strength of cement mortar were investigated. The results are introduced in the paper, some of them contribute to explain the special properties of concrete mixed with proto- machine-made sand.
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