scholarly journals Study of the Properties of Full Component Recycled Dry-Mixed Masonry Mortar and Concrete Prepared from Construction Solid Waste

2021 ◽  
Vol 13 (15) ◽  
pp. 8385
Author(s):  
Zhenwen Hu ◽  
Zhe Kong ◽  
Guisheng Cai ◽  
Qiuyi Li ◽  
Yuanxin Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Waste ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Fine Aggregate ◽  
Replacement Rate ◽  
Substitution Rates ◽  
Natural Aggregate ◽  
Mixed Mortar ◽  
Masonry Mortar

Solutions are needed to solve the problem of a large amount of construction solid waste and a shortage of natural aggregate (coarse and fine aggregates). In this paper, simple-crushed coarse aggregate (SCRCA) and simple-crushed fine aggregate (SCRFA) were obtained by simple-crushing of construction solid waste. On this basis, SCRCA and SCRFA were treated with particle-shaping to obtain particle-shaping coarse aggregate (PSRCA) and particle-shaping fine aggregate (PSRFA), and the recycled powder (RP) produced in the process of particle-shaping was collected. Under the condition of a 1:4 cement-sand ratio, RP was used to replace cement with four substitution rates of 0, 10%, 20%, and 30%, and dry-mixed masonry mortar was prepared with 100% SCRFA, PSRFA, and river sand (RS). The basic and mechanical properties and microstructure of hydration products of dry-mixed mortar were analyzed, and the maximum substitution rate of RP was determined. Under the condition that the amount of cementitious material is 400 kg/m3 and the RP is at the maximum replacement rate, three different aggregate combinations to prepare concrete are the 100% use of SCRCA and SCRFA, PSRCA and PSRFA, and RS and natural aggregate (NCA); the workability, mechanical properties, and aggregate interface transition zone of the prepared concrete were analyzed. The results show that when the replacement rate of RP is less than 20%, it has little effect on the properties of products. The performance of PSRCA and PSRFA after treatment is better than that of SCRCA and SCRFA. Under different RP substitution rates, the performance of dry-mixed mortar prepared with PSRFA is very close to that prepared with RS. The performance of recycled concrete prepared with PSRCA and PSRFA is also very close to that of products prepared with NCA and RS. The failure morphology of PSRCA and RSRFA concrete is also similar to that of NCA and RS 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.

scholarly journals Influence of Granite Cutting Waste and Recycled Concrete on Properties of Self Compacting Concrete

2019 ◽  
Vol 8 (4) ◽  
pp. 205-208
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Strength Test ◽  
Recycled Concrete ◽  
Fine Aggregate ◽  
Self Compacting Concrete ◽  
Slump Flow ◽  
Hardened Properties ◽  
Passing Ability

This paper explains the combined effect of granite cutting waste and recycled concrete on the workability and mechanical properties of self compacting concrete. Experimental plan is divided in such a way that granite cutting waste is replaced with fine aggregate at 0, 20,40,60,80 and 100% proportions. Recycled concrete is replaced with the coarse aggregate starting from 20 to 100%. Total 36 mixes were designed to check the fresh and hardened properties. Slump flow and T500, v-funnel and L-box test are conducted to know the flow ability and passing ability of concrete. To study the hardened properties compressive strength, flexural strength test values are to be collected.

Study on the Mechanical Properties and Frost Resistance of Recycled Concrete Prepared by Village Construction Wastes

2011 ◽  
Vol 418-420 ◽  
pp. 406-410
Author(s):  
Jun Liu ◽  
Yao Li ◽  
Dan Dan Hong ◽  
Yu Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Cement Mortar ◽  
Strength Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Concrete Mechanical Properties ◽  
Better Than

Abstract. Recycled aggregate—rural building material wastes pretreated by cement mortar—are applied into concrete with different replacement rates: 0, 25%, 50%, 75%, and 100%. Results from measurements of compressive strength, cleavage tensile strength, mass loss after fast freeze-thaw cycles, and compressive strength loss indicate that a different recycled aggregate replacement rate certainly influences concrete mechanical properties and frost resistance. Recycled aggregate replacement rates less than 75% performs better than common concrete. Data from the 100% replacement rate is worse than that of rates less than 75% but still satisfy the general demands of GB standard on C30 concrete.

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.

scholarly journals Recycled Concrete Aggregate for Medium-Quality Structural Concrete

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4612
Author(s):  
Dong Viet Phuong Tran ◽  
Abbas Allawi ◽  
Amjad Albayati ◽  
Thi Nguyen Cao ◽  
Ayman El-Zohairy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Pulse Velocity ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Predictive Equation ◽  
Recycled Concrete Aggregate ◽  
Structural Concrete ◽  
Medium Quality ◽  
Ultrasound Pulse

This paper reports an evaluation of the properties of medium-quality concrete incorporating recycled coarse aggregate (RCA). Concrete specimens were prepared with various percentages of the RCA (25%, 50%, 75%, and 100%). The workability, mechanical properties, and durability in terms of abrasion of cured concrete were examined at different ages. The results reveal insignificant differences between the recycled concrete (RC) and reference concrete in terms of the mechanical and durability-related measurements. Meanwhile, the workability of the RC reduced vastly since the replacement of the RCA reached 75% and 100%. The ultrasound pulse velocity (UPV) results greatly depend on the porosity of concrete and the RC exhibited higher porosity than that of the reference concrete, particularly at the transition zone between the RCA and the new paste. Therefore, the sound transmission in the RC required longer times than that in the reference concrete. Moreover, a predictive equation relating the compressive strength to the UPV was developed.

scholarly journals Predicting the Mechanical Properties of RCA-Based Concrete Using Supervised Machine Learning Algorithms

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 647
Author(s):  
Meijun Shang ◽  
Hejun Li ◽  
Ayaz Ahmad ◽  
Waqas Ahmad ◽  
Krzysztof Adam Ostrowski ◽  
...  
Keyword(s):  
Machine Learning ◽  
Mechanical Properties ◽  
Mean Square Error ◽  
Coarse Aggregate ◽  
Machine Learning Algorithms ◽  
Supervised Machine Learning ◽  
Environmental Damage ◽  
Fine Aggregate ◽  
Mean Square ◽  
The Impact

Environment-friendly concrete is gaining popularity these days because it consumes less energy and causes less damage to the environment. Rapid increases in the population and demand for construction throughout the world lead to a significant deterioration or reduction in natural resources. Meanwhile, construction waste continues to grow at a high rate as older buildings are destroyed and demolished. As a result, the use of recycled materials may contribute to improving the quality of life and preventing environmental damage. Additionally, the application of recycled coarse aggregate (RCA) in concrete is essential for minimizing environmental issues. The compressive strength (CS) and splitting tensile strength (STS) of concrete containing RCA are predicted in this article using decision tree (DT) and AdaBoost machine learning (ML) techniques. A total of 344 data points with nine input variables (water, cement, fine aggregate, natural coarse aggregate, RCA, superplasticizers, water absorption of RCA and maximum size of RCA, density of RCA) were used to run the models. The data was validated using k-fold cross-validation and the coefficient correlation coefficient (R2), mean square error (MSE), mean absolute error (MAE), and root mean square error values (RMSE). However, the model’s performance was assessed using statistical checks. Additionally, sensitivity analysis was used to determine the impact of each variable on the forecasting of mechanical properties.

Experimental Study on Mechanical Properties of Fine Aggregate Concrete Made after Wet-Sieving Coarse Aggregate

2010 ◽  
Vol 168-170 ◽  
pp. 2200-2203 ◽  
Author(s):  
Shun Bo Zhao ◽  
Na Liang ◽  
Li Xin Liu ◽  
Li Sun ◽  
Su Yang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Fine Aggregate ◽  
Concrete Wall ◽  
Aggregate Concrete ◽  
Structural Wall ◽  
Ordinary Concrete ◽  
Reinforced Composite ◽  
Wet Sieving

The validity of the wet-sieving concrete technique for building the reinforced composite concrete wall are demonstrated in the paper. The fine aggregate concrete made by ordinary concrete passing the sieve with square mash of 15 mm was cast for the surface layer, the recomposed concrete mixed by the residual concrete stayed on the sieve with the ordinary concrete was cast for the reinforced concrete structural wall. The mechanical properties such as the cubic and compressive strengths, the elastic modulus and the splitting and flexural tensile strengths of the fine aggregate concrete, the recomposed concrete and the ordinary concrete were tested and analyzed. The results show that the elastic modulus and splitting tensile strength of fine aggregate concrete reduce in some extent compared with that of ordinary concrete, the mechanical properties of recomposed concrete are almost the same as that of ordinary concrete.

Analysis and optimization of mechanical properties of recycled concrete based on aggregate characteristics

2021 ◽  
Vol 28 (1) ◽  
pp. 516-527
Author(s):  
Jiangwei Bian ◽  
Wenbing Zhang ◽  
Zhenzhong Shen ◽  
Song Li ◽  
Zhanglan Chen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Coarse Aggregate ◽  
Aggregate Size ◽  
Peak Stress ◽  
Recycled Concrete ◽  
Maximum Aggregate Size ◽  
Coarse Aggregates ◽  
Aggregate Content ◽  
Aggregate Shape

Abstract The most significant difference between recycled and natural concretes lies in aggregates. The performance of recycled coarse aggregates directly affects the characteristics of recycled concrete. Therefore, an in-depth study of aggregate characteristics is of great significance for improving the quality of recycled concrete. Based on the coarse aggregate content, maximum aggregate size, and aggregate shape, this study uses experiments, theoretical analysis, and numerical simulation to reveal the impact of aggregate characteristics on the mechanical properties of recycled concrete. In this study, we selected the coarse aggregate content, maximum aggregate size, and the aggregate shape as design variables to establish the regression equations of the peak stress and elastic modulus of recycled concrete using the response surface methodology. The results showed that the peak stress and elastic modulus of recycled concrete reach the best when the coarse aggregate content is 45%, the maximum coarse aggregate size is 16 mm, and the regular round coarse aggregates occupy 75%. Such results provide a theoretical basis for the resource utilization and engineering design of recycled aggregates.

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.

Compressive Strength of Artificial Sand Recycled Concrete with Different Content of Stone Powder

2014 ◽  
Vol 578-579 ◽  
pp. 464-468
Author(s):  
Wen Wu Lan ◽  
Rong Fu Zhong ◽  
Bo Lv ◽  
Jing Yan Gan ◽  
Jing Wei Ying
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Concrete Mixture ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregate ◽  
Different Content

This study examined the compressive behaviors of concrete with artificial sand that mixed with different content of stone powder (SP). Forty-five cubic specimens were prepared with two strength grades and five SP-content. Including 15 specimens (C35) of recycled coarse aggregate (RA) concrete with artificial sand (RCC35), 15 specimens (C45) of recycled coarse aggregate concrete with artificial sand (RCC45) and 15 specimens (C35) of natural aggregate concrete with artificial sand (NC35). The workability of concrete mixture and the compressive strength of the cubic specimens were tested. The results showed that the slump of concrete mixture decreased with the SP-content increased, and the coagulability and water retentivity of the concrete mixture were improved by using stone powder. The compressive strength of the concrete with artificial sand were increased by incorporating stone powder. The optimal SP-content of RCC35 and NC35 is 20%, while RCC45 is 10%.

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