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.

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.

Finite Element Analysis of High Strength Recycled Concrete Beam Flexural Properties

2015 ◽  
Vol 730 ◽  
pp. 11-14 ◽  
Author(s):  
Hai Long Zhang ◽  
Chang Chun Pei
Keyword(s):  
Finite Element Analysis ◽  
Concrete Beam ◽  
Coarse Aggregate ◽  
High Strength ◽  
Recycled Concrete ◽  
Replacement Rate ◽  
Element Analysis ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Recycled Coarse Aggregate

By ANSYS finite element analysis we study the impact-span moment and deflection of high strength recycled concrete beam in state of initial cracking and yield with different water-cement ratio and recycled coarse aggregate replacement rate. The results showed that: 1With the increase of water-cement ratio and recycled coarse aggregate replacement rate, the deflection is on the rise. 2With the increase of recycled coarse aggregate replacement rate, the yield moment has a slight upward trend. And with the increase of water-cement ratio and recycled coarse aggregate replacement rate, the span deflection at the state of yield has a growing trend.

Influence of Morphology of Cathode-Ray Tube Glass as Coarse Aggregates on Compressive Strength and Water Absorption of Concrete

2018 ◽  
Vol 280 ◽  
pp. 399-409
Author(s):  
Nurul Noraziemah Mohd Pauzi ◽  
Maslina Jamil ◽  
Roszilah Hamid ◽  
Muhammad Fauzi Mohd Zain
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Capillary Water ◽  
Capillary Water Absorption ◽  
Coarse Aggregates ◽  
Concrete Properties ◽  
Concrete Production ◽  
Cathode Ray Tube ◽  
Texture Size

The study on the substitution for natural coarse aggregates using waste CRT funnel glass in spherically shapes is still limited. In this paper, the waste CRT glass has been processed to form a spherical CRT glass (GS) and crushed CRT glass (GC), which were used as a coarse aggregate in concrete production. Results indicated that the inclusion of GS and GC has lower the compressive strength and decreased the rate of capillary water absorption of concrete. It was demonstrated that the morphology properties of GS and GC (shape, surface texture, size, grading) is significantly affected the concrete properties.

Microscopic Mechanism Study on Carbonation Resistance of Recycled Aggregate Concrete

2011 ◽  
Vol 194-196 ◽  
pp. 1001-1006 ◽  
Author(s):  
Hai Feng Yang ◽  
Zhi Heng Deng ◽  
Xue Liang Li
Keyword(s):  
Fly Ash ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Carbonation ◽  
Carbonation Resistance

24 100mm × 100mm × 300mm recycled concrete prisms and 96 150mm × 150mm × 150mm cubes are completed in this paper.The relationships of the carbonation depth in each carbonation age with replacement rate of recycled coarse aggregate and fly ash is studied; The SEM is used to observe the interface structure of recycled coarse aggregate concrete and compared with ordinary concrete, and finally,a recycled concrete carbonation model is proposed. The results showed that: the substitution of recycled coarse aggregate and fly ash cut down the recycled concrete carbonation resistance significantly, which are related with the replacement rate; the content of Ca(OH)2 in the recycled aggregate concrete decreased ,also there are obvious interface transition zone between the recycled coarse aggregate and the new cement;obvious cracks and large voids are exist before the recycled aggregate concrete is loaded, which lead directly to lower carbonation resistance of the recycled concrete.

Effect of Recycled Coarse Aggregate on Recycled Concrete Properties and Study of Optimum Mixture Ratio

2014 ◽  
Vol 487 ◽  
pp. 84-89
Author(s):  
Hai Long Ning ◽  
Wen Feng Zhao ◽  
Jian Liu ◽  
Shao Peng Jiao ◽  
Yi Xin Wang
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Concrete Strength ◽  
Recycled Concrete ◽  
Replacement Rate ◽  
Conventional Concrete ◽  
Mixture Ratio ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Recycled Coarse Aggregate

To study the effect of recycled coarse aggregate, water-cement ratio and mixture ratio on the physico-mechanical properties of recycled concrete, determine the finial optimum mixture ratio and physico-mechanical properties of recycled concrete with the optimum mixture ratio, physico-mechanical tests are done on recycled concrete and conventional concrete. Results show that with the replacement rate increasing of recycled coarse aggregate, the compressive strength and splitting tensile strength of recycled concrete increase and then decrease. It is feasible to develop the concrete with 100% replacement rate of recycled coarse aggregate. With an increase of recycled coarse aggregate replacement rate, dry shrinkage ratio of concrete increases gradually, but the increasing range has little effect on the concrete. The concrete strength of 28 days is linear with water-cement ratio with the correlation coefficient is 0.98763. Taking appropriate mix design, the physico-mechanical properties of recycled concrete will surpass or be equivalent to those of conventional concrete. Recycled concrete of the optimum mixing rate is the high strength with lower brittleness.

Experimental Study on Drying Shrinkage Performance of Solid Concrete Bricks Made from Recycled Coarse Aggregate

2013 ◽  
Vol 753-755 ◽  
pp. 762-770 ◽  
Author(s):  
Xi Xi He ◽  
Tao Zhang
Keyword(s):  
Moisture Content ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Drying Shrinkage ◽  
Recycled Aggregate ◽  
Test Results ◽  
Replacement Rate ◽  
Recycled Coarse Aggregate ◽  
The Impact ◽  
The Relationship

Solid recycled coarse aggregate concrete bricks were produced by QTY4-40 brick machine with strength grades of MU15-MU30. Recycled aggregate replacement rate was up to 100%. Water absorption and moisture content were tested. Two methods were taken to test the drying shrinkage. The impact of recycled aggregate replacement rate and curing period on the drying shrinkage rate, water absorption, moisture content, density was analyzed, and the relationship between them was presented. The results indicate that recycled aggregate can increase the shrinkage of solid concrete brick. The shrinkage of recycled solid concrete bricks' (fully substitute) is larger than ordinary concrete bricks' by 1.6-2 times. Water reducer is helpful to improve the water retention and decrease the shrinkage of brick. One of the test results of shrinkage got by the methods recommended in relevant specification is smaller.

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.

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