scholarly journals Uniaxial Damaged Plastic Constitutive Relation of Recycled Aggregate Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiaobin Hu ◽  
Qinwang Lu ◽  
Shanshan Cheng
Keyword(s):  
Mechanical Properties ◽  
Cyclic Loading ◽  
Constitutive Relation ◽  
Coarse Aggregate ◽  
Experimental Studies ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Test Results ◽  
Aggregate Concrete

This paper presents a proposed uniaxial damaged plastic constitutive relation of recycled aggregate concrete (RAC) based on the experimental studies. A total of five groups of RAC specimens with different recycled coarse aggregate (RCA) replacement percentages of 0, 25%, 50%, 75%, and 100%, respectively, are tested under both monotonic loading and cyclic loading. The effect of the RCA replacement percentage is thoroughly investigated on a variety of mechanical properties, including the compressive strength, the peak strain, and the elastic modulus. Based on the test results, a uniaxial damage plastic constitutive relation of the RAC is proposed within the continuous thermodynamics framework. After validated by the experimental results, the proposed damaged plastic constitutive relation of the RAC is applied to perform nonlinear analysis of the RAC columns under cyclic loading, which provides close predictions of the hysteresis behavior of the RAC columns.

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.

Study on Performance of Recycled Aggregate Concrete

2011 ◽  
Vol 477 ◽  
pp. 280-289 ◽  
Author(s):  
Shao Wei Yao ◽  
Zhen Guo Gao ◽  
Chang Rui Wang
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Physical And Mechanical Properties ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Chemical Solution ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregate ◽  
Strength And Durability

The properties of recycled coarse aggregate and the slump, the physical and mechanical properties and durability of recycled aggregate concrete were studied through tests. The results indicate that the slump, compressive strength and durability of concrete with recycled aggregate are lower than that of concrete with natural aggregate when recycled coarse aggregate fully absorbs water. However, the slump can be similar to that of concrete with natural aggregate. The properties of recycled aggregate concrete can be improved by strengthening the recycled coarse aggregate, and it is also found that the recycled coarse aggregate strengthened by grinding is superior to that soaked by chemical solution.

Experimental Research on Mechanical Properties of Recycled Aggregate Concrete under Uniaxial Loading

2013 ◽  
Vol 671-674 ◽  
pp. 1736-1740
Author(s):  
Xue Yong Zhao ◽  
Mei Ling Duan
Keyword(s):  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate

The complete stress-strain curves of recycled aggregate concrete with different recycled coarse aggregate replacement percentages were tested and investigated. An analysis was made of the influence of varying recycled coarse aggregate contents on the complete stress-strain curve, peak stress, peak strain and elastic modulus etc. The elastic modulus of RC is lower than natural concrete (NC), and with the recycled coarse aggregate contents increase, it reduces. While with the increase of water-cement ratio (W/C), recycled concrete compressive strength and elastic modulus improve significantly. In addition, put forward a new equation on the relationship between Ec and fcu of the RC.

scholarly journals Quality Improvement of Recycled Aggregate Concrete using Six Sigma DMAIC Methodology

2020 ◽  
Vol 5 (6) ◽  
pp. 1409-1419
Author(s):  
Suhas Vijay Patil ◽  
Balakrishna Rao K. ◽  
Gopinatha Nayak
Keyword(s):  
Six Sigma ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Lower Grade ◽  
Test Results ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Mix

Recycled aggregates (RA) are obtained from construction and demolished waste, laboratory crushed concrete and concrete waste at RMC plants. The concrete made from recycled aggregate is known as recycled aggregate concrete. The use of recycled aggregate is very beneficial to the environment in civil works. Its usage also helps in financial saving as the cost of transportation and production energy cost of natural coarse aggregate (NCA) is reduced. In India, the recycled aggregate application in lower grade concrete work is observed. However, the effect of recycled aggregate on the strength and durability of concrete restricts its use in higher-grade work. This paper presents a series of tests carried out on recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) and test results are compared with the NCA and parent concrete made from NCA. Tests were carried out as per IS code and concrete was prepared using a two-stage mixing approach in the concrete mix design. M30 concrete mix of four RCAC samples was tested at 28 days of curing and in comparison with parent concrete, it is found that on an average compressive strength is decreased by 12.89% at 28 days curing. Adhered mortar increases the porosity of the recycled aggregate and forms a weak zone between aggregate surface and mortar. In addition, test results showed the defects in recycled aggregate and helped to identify the area where concentration is necessary to improve the quality of recycled aggregate using six sigma DMAIC methodology. Total of 12 defects were found in the process and raw material. Statistical analysis was used to evaluate the performance of all the mix made with RCA.

Mechanical properties of recycled aggregate concrete under multiaxial compression

2020 ◽  
Vol 23 (12) ◽  
pp. 2529-2538
Author(s):  
Yumei Wang ◽  
Zhiheng Deng ◽  
Jianzhuang Xiao ◽  
Jun Sheng
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Failure Criterion ◽  
Stress Ratio ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Multiaxial Compression

The mechanical properties of recycled aggregate concrete under multiaxial compression were tested by servo-controlled setup (TAWZ-5000/3000). Properties of strength and stress–strain relation were obtained, and the influence factors of stress ratio and recycled coarse aggregate replacement ratio were analyzed. The results show that the strength of recycled aggregate concrete under multiaxial compression is higher than that of under uniaxial state, the stress ratio and recycled coarse aggregate replacement ratio have obvious effect on strength, and the shape of stress–strain curve is also varied with different levels of the two factors. Failure criterion can reflect the strength relation for recycled concrete under multiaxial stress state. Kupfer’s failure criterion is selected to describe strength properties under biaxial stress state, and the failure envelope reflects the energy absorption of different mix series. Based on octahedral stress theory, the tensile and compressive meridians have been proposed to analyze the strength characteristics under triaxial compression, and the theoretical values are well coherent with the test data.

Experiment on Properties of Recycled Aggregate Concrete

2013 ◽  
Vol 377 ◽  
pp. 99-103 ◽  
Author(s):  
Hai Tao Yang ◽  
Shi Zhu Tian
Keyword(s):  
Mechanical Properties ◽  
Abrasion Resistance ◽  
Coarse Aggregate ◽  
Objective Measure ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Replacement Ratio ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Aggregate Content

Objective: Measure and study the mechanical properties and abrasion resistance of recycled aggregate concrete in order to provide experimental basis for the application of recycled aggregate concrete in engineering. Method: Use recycled aggregate concrete with replacement ratio of recycled coarse aggregate respectively for 0%, 30%, 50%, 80% and 100% to do the slump, compressive strength, modulus of elasticity and abrasion resistance tests on them. Result: The workability of concrete decreases with the increase of recycled coarse aggregate content. Mechanical properties of concrete change as the replacement ratios of recycled coarse aggregate change. Conclusion: The recycled aggregate concrete and natural aggregate concrete have similar abrasion resistance. The recycled aggregate concrete can be applied in engineering.

scholarly journals Utilization of Demolished Waste as Coarse Aggregate in Concrete

2019 ◽  
Vol 5 (3) ◽  
pp. 540 ◽  
Author(s):  
Abdulsamee M Halahla ◽  
Mohammad Akhtar ◽  
Amin H. Almasri
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
International Standards ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Aggregate Concrete ◽  
Natural Aggregate ◽  
Concrete Building

Demolishing concrete building usually produces huge amounts of remains and wastes worldwide that have promising possibilities to be utilized as coarse aggregate for new mixes of concrete. High numbers of structures around the world currently need to be removed for several reasons, such as reaching the end of the expected life, to be replaced by new investments, or were not built by the local and international standards. Maintaining or removal of such structures leads to large quantities of concrete ruins. Reusing these concrete wastes will help in saving landfill spaces in addition to more sustainability in natural resources. The objective of this study is to investigate the possibility of using old recycled concrete as coarse aggregate to make new concrete mixes, and its effect on the evolution of the compressive strength of the new concrete mixes.  Core samples for demolished concrete were tested to determine its compressive strength. The core test results can be thought of as aggregate properties for the new concrete. Then, the compressive strength and splitting tensile strength of the new recycled aggregate concrete (RAC) were determined experimentally by casting a cubes and cylinders, respectively. It was found that the evolution of compressive strength of recycled aggregate concrete is similar in behavior to the concrete with natural aggregate, except that it is about 10% lower in values. It was also seen that water absorption for recycled aggregate is noticeably higher than that for natural aggregate, and should be substituted for in the mix design.

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 Compressive Mechanical Properties of a Novel Recycled Aggregate Concrete with Recycled Lightweight Aggregate

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Anjun Li ◽  
Gaoqiang Zhou ◽  
Xianggang Zhang ◽  
Ercong Meng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Lightweight Aggregate ◽  
Ultimate Strain ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Replacement Ratio ◽  
Stress Strain ◽  
Aggregate Concrete

A novel recycled aggregate concrete was prepared by replacing the natural aggregate with recycled lightweight aggregate. Subsequently, the mechanical properties and compressive stress-strain constitutive relation of the recycled lightweight aggregate concrete (RLWAC) were explored. For this purpose, the recycled lightweight aggregate (RLWA) replacement ratio (0%, 25%, 50%, 75%, and 100%) was selected as a variable, and the compressive strength of 15 cube and 30 prism specimens was evaluated. The failure morphology of the specimen was subsequently characterized, along with the cubic compressive strength, axial compressive strength, peak strain, ultimate strain, and other performance indices. The influence of the replacement ratio for the specimen indices of the RLWAC was also analyzed. It was observed that the dry apparent density of RLWAC decreased gradually on increasing the replacement ratio. Compared with 0% replacement ratio, a decrease of 6.50%, 11.39%, 21.84%, and 27.54% was observed, respectively. On enhancing the RLWA replacement ratio, the compressive strength, peak strain, and ultimate strain of RLWAC were observed to be gradually reduced. As the replacement ratio was increased from 75% to 100%, the peak strain was noted to decrease the most by about 6.8%. As the replacement ratio was increased from 50% to 75%, the ultimate strain decreased the most by about 14.2%. Based on the experimental findings, the functional relationships of the strength indices and the conversion value of each strength index with the replacement ratio were also established. Finally, based on the model proposed by the existing model, the stress-strain equation of RLWAC was developed, and the fitting results were observed to be in good agreement with the test results.

scholarly journals Water-glass Module on Mechanical Properties of Geopolymer Recycled Aggregate Concrete

2022 ◽  
Vol 2148 (1) ◽  
pp. 012060
Author(s):  
Zhaoyang Ding ◽  
Qun Su ◽  
Hongguan Bian ◽  
Qing Wang ◽  
Jinghai Zhou
Keyword(s):  
Mechanical Properties ◽  
Water Glass ◽  
Elasticity Modulus ◽  
Peak Stress ◽  
Hydration Product ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
National Standard ◽  
Peak Strain ◽  
Aggregate Concrete

Abstract Geopolymer recycled aggregate concrete (GRAC) was prepared by replacing cement with geopolymer and natural aggregate with wast concrete. The effect of water-glass modules on mechanical properties of GRAC was studied. It was found that there are tow kind of binding structures in geopolymer hydration product: C-A-S-H and N-A-S-H, they both contribute to the strength of GRAC. The value of size conversion coefficient of current national standard is inapplicable for GRAC, the calculation method of which is given in this paper. Elasticity modulus and peak stress of GRAC is proportional to water-glass modulus, and peak strain is inversely proportional and its constitutive equation was established.

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