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.

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 Research on Main Properties of New Recycled Coarse Aggregate Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 19-23 ◽  
Author(s):  
Da Xing Qian ◽  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Jong Hoe Kim
Keyword(s):  
Concrete Beam ◽  
Coarse Aggregate ◽  
Economic Benefits ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Secondary Process ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Waste Concrete

Recently reutilization of waste concrete becomes one of the hottest issues in civil engineering field throughout the world. However, most of the concerned research focuses on the RCA (recycled coarse aggregate) by simply crushing waste concrete. In this paper shucking technique is developed to secondary process the simply crushing waste concrete for improving the performance of RCA concrete. Test has been done to demonstrate that performances such as strength, elastic modulus et al. of shucking RCA concrete is better than those of common recycled concrete. Simultaneously, beam specimens are made to test the flexural behavior of shucking RCA concrete. Results showed that the deflection of shucking RCA concrete beam is approximately same with that of natural coarse aggregate concrete beam, which solves current problem that recycled aggregate concrete beam has bigger deflection than common concrete beam. The new shucking technique developed in this paper has many advantages to be applied in practical engineering and it has obvious economic benefits and social effect.

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.

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.

The Effect of Water-Cement Ratio and Curing Age on the Strength of Recycled Concrete

2011 ◽  
Vol 217-218 ◽  
pp. 740-745
Author(s):  
Xue Bing Zhang ◽  
Chen Gang Kuang ◽  
Zhi Fang
Keyword(s):  
Growth Rate ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Empirical Formulas ◽  
Natural Sand ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Ordinary Concrete ◽  
Effect Of Water ◽  
Curing Age

The effect of water-cement ratio and curing age on the strength of recycled concrete was studied by experiment with the combination of the recycled coarse aggregate adding natural sand. The results showed that with the increase of curing age, the greater the water-cement ratio is, the smaller the strength growth rate is; the smaller the water-cement ratio is, the greater the strength growth rate is. There is a relatively larger increase in the growth rate of 90d strength than 28d’, which is significantly higher than that of the ordinary concrete. The linear relationship between water-cement ratio and strength of recycled concrete is worse than that of ordinary concrete. Under the same water-cement ratio and curing age, the strength of recycled concrete is lower than that of ordinary concrete, and the empirical formulas between the strength of 28d and 7d, 90d and 28d were obtained.

Experimental Study on Flexural Behavior of Recycled Coarse Aggregate Concrete Beam

2010 ◽  
Vol 29-32 ◽  
pp. 543-548 ◽  
Author(s):  
Wen Hui Bai ◽  
Bin Xiang Sun
Keyword(s):  
Concrete Beam ◽  
Coarse Aggregate ◽  
Bending Moment ◽  
Structure Design ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Normal Section ◽  
Recycled Coarse Aggregate

In order to investigate flexural behavior of simply-supported beam using recycled coarse aggregate concrete, the difference of the component normal section stress distortion performance and failure characteristic between the recycled concrete beam and the normal concrete beam is researched. The approaches of testing the flexural behavior of 6 recycled course aggregate beams with the same section size, different replacement ratio of recycled coarse aggregate (0%, 50%, 70% and 100%) and different percentage reinforcement (0.68%, 0.89% and 1.13%). Based on the experimental the following conclusions are draw. There are also 4 phases of elasticity, cracking, yield and ultimate during the stress course of recycled concrete beam component normal section stress; the average strain measured on cross-section obliges to the plane section assumption; the characteristics of stress distortion and destruction of recycled concrete beam are basically the same as those of the normal concrete beam. Under same conditions, the cracking moment and the ultimate flexural carrying capability of recycled concrete beam is almost the same as those of normal concrete beam. The deformation of recycled concrete beam is larger than concrete beam. The conclusion of the paper is that it is still feasible to calculate the ultimate bending moment, cracking moment, and the biggest crack width of recycled concrete beam according to the formula in China Concrete Structure Design Code, but the deflection formula needs to be adjusted.

Flexural properties of steel fiber types and reinforcement ratio for high-strength recycled concrete beams

2017 ◽  
Vol 20 (10) ◽  
pp. 1512-1522 ◽  
Author(s):  
Hai-Long Zhang ◽  
Chang-Chun Pei
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Crack Width ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
High Strength ◽  
Recycled Concrete ◽  
Steel Fibers ◽  
Flexural Properties ◽  
Recycled Coarse Aggregate

This article took fly ash and silica fume as cementing materials to replace part of cement and took recycled coarse aggregate to replace part of gravel to mix plain concrete and studied the flexural properties of the beams with high-strength steel fiber–recycled concrete by changing the types of steel fiber and reinforcement ratio. The results showed that fly ash and silica fume could improve strength and flexural capacity of the recycled concrete beam by filling micro-cracks of recycled coarse aggregate and reduce the development speed of deflection and crack width of the test beam. Steel fibers could significantly slow the development of deflection and crack width of the beams with high-strength recycled concrete, and the difference in end-structure could increase the flexural capacity of the beams in varying degrees. The article put forward theory of improving the bearing capacity of the beam with three kinds of steel fibers by introducing the influence factor of steel fiber end-structure.

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