scholarly journals Study on capillary water absorption properties of polypropylene fibre coal gangue ceramsite concrete under freeze-thaw damage

2020 ◽  
Vol 2020 (3) ◽  
pp. 98-103 ◽  
Author(s):  
Jisheng Qiu ◽  
Peng Guo ◽  
Min Xing ◽  
Xiao Guan ◽  
Guanghong Xiong
Keyword(s):  
Water Absorption ◽  
Polypropylene Fibre ◽  
Coal Gangue ◽  
Capillary Water ◽  
Absorption Properties ◽  
Capillary Water Absorption ◽  
Freeze Thaw

scholarly journals Effects of Imposed Damage on the Capillary Water Absorption of Recycled Aggregate Concrete

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Qi Gao ◽  
Zhiming Ma ◽  
Jianzhuang Xiao ◽  
Fuan Li
Keyword(s):  
Absorption Coefficient ◽  
Water Absorption ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Capillary Absorption ◽  
Capillary Water ◽  
Aggregate Concrete ◽  
Capillary Water Absorption ◽  
Freeze Thaw ◽  
Loading Level

Capillary water absorption of concrete is closely related to its pore structure, permeability, and durability. This paper intensively investigates the effects of imposed damage, including freeze-thaw damage and loading damage, on the capillary water absorption of recycled aggregate concrete (RAC). Freeze-thaw cycle test, loading test, and the experiment of capillary water absorption were carried out, respectively. The results demonstrate that the addition of recycled coarse aggregate (RCA) results in the increase in the capillary absorption behavior of RAC without imposed damage, and there exists a linear correlation between the behaviors of capillary water absorption and chloride penetration of RAC. The imposed freeze-thaw damage or load damage of RAC boosts with the increase of RCA replacement percentages after suffering the same freeze-thaw cycles or loading level. The imposed freeze-thaw damage and load damage further lead to the increase in the capillary water absorption of RAC, and the capillary absorption coefficient of RAC increases linearly with the increased RCA replacement percentages, after suffering the same freeze-thaw cycles or loading level. Furthermore, capillary absorption coefficient increases linearly with the growth of imposed freeze-thaw damage or load damage degree, which can be used to estimate the capillary absorption behavior of RAC exposed to the extreme environment.

scholarly journals Capillary Water Absorption Characteristics of Recycled Concrete in Freeze-Thaw Environment

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Qianhui Xiao ◽  
Xiaolin Liu ◽  
Jisheng Qiu ◽  
Yangyang Li
Keyword(s):  
Prediction Model ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Capillary Water ◽  
Replacement Rate ◽  
Capillary Water Absorption ◽  
Freeze Thaw ◽  
Recycled Coarse Aggregate ◽  
Absorption Characteristics

In order to study the capillary water absorption characteristics of recycled concrete (RAC) with different replacement rates of recycled coarse aggregate (0, 20%, 40%, and 60%) in freeze-thaw environment, the standard test method of measuring the water absorption of hydraulic cement concrete (ASTM C1585-13) was adopted, and the influence mechanism of freeze-thaw cycle and replacement rate of recycled coarse aggregate on the capillary water absorption of RAC was analyzed, and a prediction model of initial capillary water absorption of RAC in freeze-thaw environment was established. The results show that when the freeze-thaw environment is the same, the greater the replacement rate of recycled coarse aggregate, the greater the cumulative water absorption of RAC, the faster the initial capillary water absorption, and the stronger the capillary water absorption; when the freeze-thaw environment is different, the more the freeze-thaw cycles, the greater the cumulative water absorption of RAC with the same replacement rate of recycled coarse aggregate, the faster the initial capillary water absorption, and the stronger the capillary water absorption. The prediction model of RAC initial capillary water absorption established by regression analysis has high accuracy, which can be used to predict RAC capillary water absorption performance and provide theoretical basis for the research of RAC frost resistance durability.

Influence of Water Repellent Surface Impregnation on Water Absorption Properties of Recycled Aggregate Concrete

2011 ◽  
Vol 71-78 ◽  
pp. 5011-5014 ◽  
Author(s):  
Ya Guang Zhu ◽  
Pei Zhen Xu ◽  
Qiu Yi Li ◽  
Chuan Li
Keyword(s):  
Surface Water ◽  
Water Absorption ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Water Repellent ◽  
Capillary Water ◽  
Absorption Properties ◽  
Aggregate Concrete ◽  
Capillary Water Absorption

This paper aimed to investigate the influence of using silane surface water repellent treatment on the capillary water absorption properties of recycled aggregate concrete. In this study, two types of coarse aggregate, natural aggregates and recycled aggregates were used, and the surface water repellent treatment of concrete was produced by brushing 100g/m2 and 200g/m2 of paste. It was found that the silane impregnation depth of recycled concrete was deeper than that of natural concrete, and the surface treatment was more effective in the improvement of capillary water absorption properties of recycled aggregate concrete than the natural aggregate concrete.

scholarly journals Effect of Capillary Water Absorption on Electrical Resistivity of Concrete with Coal Gangue Ceramsite as Coarse Aggregates

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Dong Li ◽  
Shi Liu ◽  
Haiqing Liu
Keyword(s):  
Water Absorption ◽  
Absorption Capacity ◽  
Coal Gangue ◽  
Capillary Water ◽  
Capillary Suction ◽  
Capillary Action ◽  
Capillary Water Absorption ◽  
Coarse Aggregates ◽  
The Matrix ◽  
Water Transmission

This study intends to access the influence of the capillary action on electrical property of the concrete containing the coal gangue ceramsite. For this purpose, four kinds of concrete samples were prepared; the coal gangue ceramsite was adopted at four volume ratios of 0%, 30%, 60%, and 100%, respectively. The resistivity of the samples was explored using the two-electrode method during the capillary action. The effects of the coal gangue ceramsite contents on capillary water absorption capacity and resistivity of the matrix were verified. The variation of the resistivity of the matrix under the influence of capillary water transmission was analyzed. The results demonstrated that, for the unsaturated concrete, the resistivity of the matrix increased with the increment of the coal gangue ceramsite dosage. The electrical properties of the concrete were affected noticeably by the capillary water absorption of the matrix; the resistivity of the matrix dropped significantly under the capillary suction, which may be attributed to the formation of the new conductive channels caused by the absorbed water. The variation of the resistivity of the concrete under the capillary suction sustained the two-stage reduction curve. The ability of the capillary water absorption of concrete was enhanced with the addition of coal gangue ceramsite, compared to the traditional aggregates concrete, the initial sorptivity, and secondary sorptivity of the matrix increased by 47% and 16% with the 100% content of coal gangue ceramsite. However, during the process of the capillary suction, the resistivity of the coal gangue ceramic concrete was always greater than that of the concrete with traditional crushed aggregates.

scholarly journals The Influence of 30 Years Outdoor Weathering on the Durability of Hydrophobic Agents Applied on Obernkirchener Sandstones

Buildings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
Jeanette Orlowsky ◽  
Franziska Braun ◽  
Melanie Groh
Keyword(s):  
Water Absorption ◽  
Water Uptake ◽  
Capillary Water ◽  
Capillary Water Absorption ◽  
Absorption Determination ◽  
Colour Changes ◽  
Uptake Velocity ◽  
Outdoor Weathering

The durability of eleven different water repellents applied on one sandstone type was studied after a long-term weathering at seven different locations in Germany. By measuring colour changes, it could be shown that the formation of black crusts, the deposition of particles and biogenic growth caused a gradual darkening as well as significant changes in total colour over time. Additionally, the water absorption behaviour was investigated with two different methods: applying a low pressure using the pipe method and capillary water absorption measurements from a wet underlay. Afterwards, the test results were analysed with four different evaluation methods: calculation of the protection degree from pipe method and capillary water absorption, determination of the velocity of water uptake during capillary water absorption and calculation of the damaged depth of the stone surface using single-sided NMR technique. The growing damaged depth leads to an increase of the water uptake velocity and to a decrease of the protection degree of the applied hydrophobing agents. Three protective agents based on isobutyltrimethoxysilane showed already after two years of outdoor weathering a clear loss of performance, which significantly increased after 30 years of exposure.

scholarly journals Analysis of the Effect of Nano-SiO2 and Waterproofing Agent on the Water Transportation Process in Mortar Using NMR

2020 ◽  
Vol 10 (21) ◽  
pp. 7867
Author(s):  
Tao Meng ◽  
Huadong Wei ◽  
Kanjun Ying ◽  
Menghua Wang
Keyword(s):  
Water Absorption ◽  
Moisture Diffusion ◽  
Test Results ◽  
Capillary Water ◽  
Process Data ◽  
Capillary Water Absorption ◽  
Nano Sio2 ◽  
Water Transportation ◽  
Cement Based Materials ◽  
Transportation Process

Moisture diffusion in cement-based materials significantly impacts its durability. In this study, we analyzed the effect of adding a waterproofing agent and nano-SiO2 (NS) on the water transportation process in mortar using capillary water absorption tests and nuclear magnetic resonance (NMR) technology. The results indicate that the combined action of the waterproofing agent and nano-SiO2 drastically reduce the capillary water absorption coefficient and have a more significant impact than only adding the waterproofing agent. The moisture diffusion in different sections of the mortar during the water absorption process is obtained from the NMR test results and two function models. Comparative studies indicate that the NMR test results have good correlation with the capillary water absorption test results and provide accurate process data. The NMR analysis results offer a new analytical method to characterize the porosity of cement-based materials by continuously monitoring small-pitch sections.

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