scholarly journals Experimental Study on the Mechanical Properties and Compression Size Effect of Recycled Aggregate Concrete

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2323
Author(s):  
Yubing Du ◽  
Zhiqing Zhao ◽  
Qiang Xiao ◽  
Feiting Shi ◽  
Jianming Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Size Effect ◽  
Compressive Stress ◽  
Failure Modes ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Substitution Ratio ◽  
The Impact

To explore the basic mechanical properties and size effects of recycled aggregate concrete (RAC) with different substitution ratios of coarse recycled concrete aggregates (CRCAs) to replace natural coarse aggregates (NCA), the failure modes and mechanical parameters of RAC under different loading conditions including compression, splitting tensile resistance and direct shear were compared and analyzed. The conclusions drawn are as follows: the failure mechanisms of concrete with different substitution ratios of CRCAs are similar; with the increase in substitution ratio, the peak compressive stress and peak tensile stress of RAC decrease gradually, the splitting limit displacement decreases, and the splitting tensile modulus slightly increases; with the increase in the concrete cube’s side length, the peak compressive stress of RAC declines gradually, but the integrity after compression is gradually improved; and the increase in the substitution ratio of the recycled aggregate reduces the impact of the size effect on the peak compressive stress of RAC. Furthermore, an influence equation of the coupling effect of the substitution ratio and size effect on the peak compressive stress of RAC was quantitatively established. The research results are of great significance for the engineering application of RAC and the strength selection of RAC structure design.

scholarly journals Impact Properties of Recycled Aggregate Concrete with Nanosilica Modification

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xingguo Wang ◽  
Fei Cheng ◽  
Yixin Wang ◽  
Xianggang Zhang ◽  
Haicheng Niu
Keyword(s):  
Mechanical Properties ◽  
Split Hopkinson Pressure Bar ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Aggregate Concrete ◽  
Dynamic Increase Factor ◽  
The Impact

The optimal soaking time and nanosilica concentration were chosen by the physical properties of the nanosilica-modified recycled aggregate. Recycled aggregate concrete (RAC) and nanosilica recycled aggregate concrete (SRAC) were fabricated by using ordinary recycled aggregate and nanosilica-modified recycled aggregate. Based on the comparative experimental study of basic mechanical properties, the effects of nanosilica recycled aggregate(SRA) modification and recycled aggregate(RA) replacement percentage on the basic mechanical properties of recycled concrete were analyzed. Finally, the split-Hopkinson pressure bar (SHPB) was used to conduct comparative experimental research on the impact resistance of recycled aggregate concrete and nanosilica-modified recycled aggregate concrete. The effects of nanosilica recycled aggregate modification and aggregate replacement percentage on failure morphology, dynamic peak stress, dynamic increase factor (DIF), dynamic peak strain were analyzed.

Study on the Basic Mechanical Properties of Recycled Concrete Hollow Block Masonry

2013 ◽  
Vol 438-439 ◽  
pp. 749-755 ◽  
Author(s):  
Tong Hao ◽  
Dong Li
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Shear Behavior ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Aggregate Concrete ◽  
Mortar Strength ◽  
Hollow Block

By the experimental studying on the basic mechanical properties of recycled concrete hollow block masonry, the compressive and shear behavior of recycled aggregate concrete hollow block masonry under different mortar strength were analyzed. Research indicated that the compressive and shear behavior of recycled aggregate concrete hollow block masonry was similar to that of ordinary concrete hollow block masonry. The normal formula was recommended to calculate the compressive strength of the masonry. The shear strength of the masonry was affected by the mortar strength. The shear strength calculation formula of recycled concrete hollow block masonry was proposed according to the formula of masonry design code. The calculating results were in good agreement with the test results.

Meso-Analysis of Dynamic Compressive Behavior of Recycled Aggregate Concrete Using BFEM

2019 ◽  
Vol 17 (06) ◽  
pp. 1950013 ◽  
Author(s):  
Liping Ying ◽  
Yijiang Peng ◽  
Hongming Yang
Keyword(s):  
Mechanical Properties ◽  
High Strain ◽  
Dynamic Mechanical Properties ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Dynamic Mechanical ◽  
Concrete Materials ◽  
Dynamic Damage

In this paper, the base force element method (BFEM) for dynamic damage problems is proposed. And the BFEM model was applied to investigate the dynamic mechanical behavior of recycled aggregate concrete (RAC). Any convex polygon recycled aggregate was simulated. A constitutive relationship of dynamic damage was given. The compression test under dynamic loadings on the recycled concrete specimen was simulated. The stress–strain softening curve, variation law of dynamic enhancement coefficient and the damage pattern were researched under different strain rates. The dynamic properties of recycled concrete materials at high strain rate are also studied. The effect of different aggregate distribution on the mechanical properties of concrete was studied. The results of dynamic calculation of recycled concrete materials by this method are compared with the experimental results. The numerical simulation results are in good agreement with the experimental results. The comparative analysis on the dynamic mechanical properties of RAC and natural aggregate concrete (NAC) was also studied. The results show that the BFEM can be used to analyze the dynamic mechanical properties of RAC and NAC under high strain rate, and can be used for large-scale engineering calculations.

scholarly journals Basic Mechanical Properties of Basalt Fiber Reinforced Recycled Aggregate Concrete

2017 ◽  
Vol 11 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Huaxin Liu ◽  
Jianwei Yang ◽  
Xiangqing Kong ◽  
Xuxu Xue
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Basalt Fiber ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mixing Ratio ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Chopped Basalt Fiber

In order to study the basic mechanical properties of basalt fiber reinforced recycled aggregate concrete, the concrete mix ratio, the length and the volume mixing ratio of chopped basalt fiber yarn are designed for changing factors. A total of 324 specimens have been completed for this investigation. The compressive strength, splitting tensile strength, elastic modulus and axial compressive strength of basalt fiber recycled concrete have carried on the experimental study and theoretical analysis as 81 specimens, respectively. In all specimens, coarse aggregate were replaced by recycled aggregate with a replacement rate of 100%. Experimental results show that the failure process and failure pattern of basalt fiber recycled concrete and ordinary concrete are similar; With the improvement of concrete strength grade; When the volume mixing ratio of chopped basalt fiber yarn is 0.2%, the mechanic performance can effectively improve, and the length of chopped basalt fiber has less effect on the mechanical indexes; The conversion relation between common concrete mechanics index is no longer suitable for basalt fiber recycled concrete, new conversion formulas for basalt fiber recycled concrete between the mechanics index were presented through fitting experimental data.

scholarly journals Mechanical Properties of Recycled Aggregate Concrete at Low and High Water/Binder Ratios

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Gai-Fei Peng ◽  
Yan-Zhu Huang ◽  
Hai-Sheng Wang ◽  
Jiu-Feng Zhang ◽  
Qi-Bing Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fracture Energy ◽  
Main Type ◽  
High Water ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Heating Process ◽  
Aggregate Concrete

This paper presents an experimental research on mechanical properties of recycled aggregate concrete (RAC) at low and high water/binder (W/B) ratios. Concrete at two W/B ratios (0.255 and 0.586) was broken into recycled concrete aggregates (RCA). A type of thermal treatment was employed to remove mortar attached to RCA. The RAC at a certain (low or high) W/B ratio was prepared with RCA made from demolished concrete of the same W/B ratio. Tests were conducted on aggregate to measure water absorption and crushing values and on both RAC and natural aggregate concrete (NAC) to measure compressive strength, tensile splitting strength, and fracture energy. The mechanical properties of RAC were lower than those of NAC at an identical mix proportion. Moreover, the heating process caused a decrease in compressive strength and fracture energy in the case of low W/B ratio but caused an increase in those properties in the case of high W/B ratio. The main type of flaw in RCA from concrete at a low W/B ratio should be microcracks in gravel, and the main type of flaw in RCA from concrete at a high W/B ratio should be attached mortar.

scholarly journals Mechanical Property Tests and Strength Formulas of Basalt Fiber Reinforced Recycled Aggregate Concrete

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1851 ◽  
Author(s):  
Sheng-En Fang ◽  
Hua-Shan Hong ◽  
Pei-Hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Failure Modes ◽  
Volume Fraction ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Volume Fractions

In order to investigate the influence of basalt fibers (BFs) on the mechanical performance of recycled aggregate concrete (RAC), some groups of RAC specimens were first tested involving different types of fibers such as carbon fibers, steel fibers, polypropylene fibers and hybrid fibers. The main four indices for the investigation consisted of cube compressive strengths, axial compressive strengths, splitting tensile strengths and Young’s modulus. The effects of fiber volume fractions on the RAC slumps were also discussed. Meanwhile, the mechanical properties and failure modes of the BF-reinforced RAC were compared with those of other fiber-reinforced RAC and common concrete (CC). Subsequently the optimal volume fractions of BFs were explored for different mechanical properties within the volume fraction range of 0–0.2%. The back propagation neural networks were further applied to predict and validate the optimal BF fractions. Lastly, the general strength formulas, as well as the elastic modulus formula, for BF-reinforced RAC were deducted based on the specimen test results. It is found that the addition of fibers may improve the failure modes of RAC and different fibers present positive or negative effects on the mechanical properties. The optimal volume fractions of BF with respect to the four mechanical indices are 0.1%, 0.15%, 0.1% and 0.2% respectively. The proposed strength and elastic modulus formulas of BF-reinforced RAC provide satisfactory predictions with the test results and thus can be used as a reference in practice.

scholarly journals Influence of Wetting and Drying Cycles on Physical and Mechanical Behavior of Recycled Aggregate Concrete

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5675
Author(s):  
Caroline S. Rangel ◽  
Mayara Amario ◽  
Marco Pepe ◽  
Enzo Martinelli ◽  
Romildo D. Toledo Filho
Keyword(s):  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Wetting And Drying ◽  
Aggregate Concrete ◽  
Wetting And Drying Cycles ◽  
The Impact

Recently, concerns have been rising about the impact of increasing the depletion of natural resources and the relevant generation of construction and demolition waste, on the environment and economy. Therefore, several efforts have been made to promote sustainable efficiency in the construction industry and the use of recycled aggregates derived from concrete debris for new concrete mixtures (leading to so-called recycled aggregate concrete, RAC) is one of the most promising solutions. Unfortunately, there are still gaps in knowledge regarding the durability performances of RAC. In this study, we investigate durability of structural RAC subjected to wet-dry cycles. We analyze the results of an experimental campaign aimed at evaluating the degradation process induced by wetting and drying cycles on the key physical and mechanical properties of normal- and high-strength concrete, produced with coarse recycled concrete aggregates (RCAs) of different sizes and origins. On the basis of the results we propose a degradation law for wetting and drying cycles, which explicitly makes a possible correlation between the initial concrete porosity, directly related to the specific properties of the RCAs and the resulting level of damage obtained in RAC samples.

scholarly journals Size Effect on Recycled Concrete Strength and Its Prediction Model Using Standard Neutrosophic Number

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
X. Peng ◽  
Q. W. Yang ◽  
F. J. Qin
Keyword(s):  
Size Effect ◽  
Size Effects ◽  
Concrete Strength ◽  
Engineering Application ◽  
Specimen Size ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Neutrosophic Number

In recent years, research on recycled aggregate concrete has become a hot issue in the field of civil engineering. This paper mainly studies the size effects on compressive and tensile strengths of the recycled aggregate concrete. Firstly, four sets of recycled concrete cube specimens with different sizes are produced in the laboratory. Secondly, the experiments on compressive and tensile strengths are carried out to obtain the rules of the strength value with the change of the specimen size. Thirdly, a standard neutrosophic number is proposed and used in modelling the size effect law more reasonably. According to the experimental results, it was found that the compressive and tensile strengths of recycled concrete both have obvious size effects. In general, the strength value decreases gradually with the increase of specimen size. Using the standard neutrosophic number, the proposed new formula on size effect law is more suitable for tackling the indeterminacy in the experimental data. It has been shown that the size effect law based on the standard neutrosophic number is more realistic than the existing size effect law. The results may be useful for the engineering application of the recycled concrete and can be extended to other types of size effect laws in the future.

Research on the Characteristics and Status of Recycled Concrete Filled Steel Tube

2014 ◽  
Vol 580-583 ◽  
pp. 2320-2323
Author(s):  
Bing Wang ◽  
Xiao Liu ◽  
Xiao Yu
Keyword(s):  
Mechanical Properties ◽  
Environmental Protection ◽  
Steel Tube ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Future Application ◽  
Aggregate Concrete ◽  
Concrete Filled Steel Tube ◽  
Waste Concrete

Utilization of waste concrete has a great significance for environmental protection; concrete filled steel tube is a way of utilization of waste concrete. At the same time, the recycled concrete on the center tube has a "hoop" function, can compensate for the deviation of mechanical properties of recycled aggregate concrete. This paper introduces the characteristics of steel recycled concrete, and introduces the research status of domestic experts and scholars on it, based on the above; the future application of the recycled concrete in steel pipe is presented.

Influence of Amount of Recycled Coarse Aggregate on Mechanical Properties of Steel Tube Columns

2013 ◽  
Vol 647 ◽  
pp. 748-752 ◽  
Author(s):  
Min Hou ◽  
Lang Li ◽  
Jiang Feng Dong ◽  
Qing Yuan Wang
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
Compressive Loading ◽  
Physical And Mechanical Properties ◽  
Steel Tube ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

This paper presents the experimental results of recycled aggregate concrete filled steel tube columns prepared with different amount of recycled coarse aggregate (RCA) subjected to axial loading. The recycled coarse aggregates are obtained from the earthquake waste in Sichuan. Based on the studying of the physical and mechanical properties of recycled coarse aggregate, the mechanical property of recycled aggregate concrete (RAC) with five concrete mixes with 0%, 25%, 50%, 75% and 100% RCA respectively are prepared. The behaviour of the circular solid steel tube columns are studied in terms of the load carrying capacity, ductility and strain response under axial compressive loading in addition to the physical and mechanical characteristics of RCA and RAC. The results show that the steel tube column gives lower ultimate bearing capacities when the RCA were added. However, no obvious difference on the failure modes were found between the steel tube columns filled with recycled aggregate concrete and normal concrete.

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