Prediction of compressive strength of recycled aggregate concrete based on gray correlation analysis

Today, efforts are underway in a number of areas to conserve the environment and protect natural resource. In the construction industry, many researchers have studied the development of new concrete using recycled aggregate (RA). This research proposes a multiple regression model (MRM) for predicting the compressive strength of recycled aggregate concrete (RAC). The compressive strength data of 85 specimens of RAC strengths were used for constructing and evaluating the prediction model. The average error rate of the constructed MRM evaluation is 7.18 percent. This result will be useful for predicting the compressive strength of RAC using multiple regression analysis.

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Experimental Study on Compressive Strength of Recycled Aggregate Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.385-387.381 ◽

2008 ◽

Vol 385-387 ◽

pp. 381-384 ◽

Cited By ~ 3

Author(s):

Wei Wang ◽

Hua Ling ◽

Xiao Ni Wang ◽

Tian Xia ◽

Da Zhi Wang ◽

...

Keyword(s):

Experimental Study ◽

Compressive Strength ◽

Coarse Aggregate ◽

Recycled Aggregate Concrete ◽

Time Dependent ◽

Recycled Aggregate ◽

Experimental Investigations ◽

Aggregate Concrete ◽

Cement Ratio ◽

Practical Engineering

With the increase in the use of recycled aggregate concrete (RAC), it is necessary to clearly understand its behavior and characteristics. In this paper, experimental study on compressive strength of RAC with same water/cement ratio is conducted. Firstly, influence of recycled coarse aggregate contents on cube compressive strength of RAC is studied. Secondly, experiment on time-dependent strength developing process of RAC is conducted with different solidification ages. Finally, based on above experimental investigations, empirical formula for compress strengths of RAC with different ages is presented. The result of this paper is helpful to theoretical analysis and practical engineering design of RAC structures.

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Experimental study on the compressive strength, damping and interfacial transition zone properties of modified recycled aggregate concrete

Royal Society Open Science ◽

10.1098/rsos.190813 ◽

2019 ◽

Vol 6 (12) ◽

pp. 190813

Author(s):

Bin Lei ◽

Huajian Liu ◽

Zhimin Yao ◽

Zhuo Tang

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Transition Zone ◽

Loss Factor ◽

Steel Fibre ◽

Interfacial Transition Zone ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Damping Properties ◽

Aggregate Concrete

At present, many modification methods have been proposed to improve the performance of recycled aggregate concrete (RAC). In this study, tests on the compressive strength and damping properties of modified RAC with the addition of different proportions of recycled coarse aggregate (RCA) (0, 50, 100%), rubber powder (10, 15, 20%), steel fibre (5, 7.5, 10%) and fly ash (15, 20, 5%) are carried out. To elucidate the effect of the modification method on the interfacial transition zone (ITZ) performance of RAC, model ITZ specimens are used for push-out tests. The results show that when the replacement rate of RCA reaches 100%, the loss factor of the RAC is 6.0% higher than that of natural aggregate concrete; however, the compressive strength of the RAC decreases by 22.6%. With the addition of 20% rubber powder, the damping capacity of the modified RAC increases by 213.7%, while the compressive strength of the modified RAC decreases by 47.5%. However, with the addition of steel fibre and fly ash, both the compressive strength and loss factor of the RAC specimens increase. With a steel fibre content of 10 wt%, the compressive strength and loss factor of the RAC increase by 21.9% and 15.2%, respectively. With a fly ash content of 25 wt%, the compressive strength and loss factor of the RAC increase by 8.6% and 6.9%, respectively. This demonstrates that steel fibre and fly ash are effective in improving both the damping properties and compressive strength of RAC, and steel fibre is more effective than fly ash. Two methods were used for modification of the RAC: reinforcing the RCA through impregnation with a 0.5% polyvinyl alcohol (PVA) emulsion and nano-SiO 2 solution, and strengthening the RAC integrally through the addition of fly ash as an admixture. Both of these techniques can improve the ITZ bond strength between the RAC and new mortar. Replacing 10% of the cement with fly ash in the new mortar is shown to be the best method to improve the ITZ strength.

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Quality Improvement of Recycled Aggregate Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.302-303.308 ◽

2006 ◽

Vol 302-303 ◽

pp. 308-313 ◽

Cited By ~ 4

Author(s):

Vivian W.Y. Tam ◽

X.F. Gao ◽

C.M. Tam

Keyword(s):

Compressive Strength ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Two Stage ◽

New Approach ◽

Aggregate Concrete ◽

Strength Based ◽

Mixing Method ◽

Strength Variability

The developments of recycled aggregate concrete pressing hard in construction activities; however, the limitations on their applications had never being ended. The focus of this paper is: i) investigating the waste management strategy in construction; ii) proposing the two-stage mixing approach (TSMA) to improve the quality of RAC; and iii) experimenting the TSMA and assessing the benefits possibly gained. It proposes a new approach in mixing concrete, namely, the two-stage mixing method, to improve compressive strength of RAC and lower its strength variability. The replacement ratio from zero to thirty is under experiment on their compressive strength. Based upon the experimental results, improvements of 31 % in strength at 28 days with 30 % RA substitute was achieved. The effect can be attributably to the porous nature of the RA and the pre-mix process which can make some pores filled up resulting in a denser concrete and thus leading to higher strength when compared with the traditional mixing approach. Therefore, two-stage mixing approach can open up a wider application of recycled aggregate concrete.

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Probabilistic Conversion of the Compressive Strength of Cubes to Cylinders of Natural and Recycled Aggregate Concrete Specimens

Materials ◽

10.3390/ma12020280 ◽

2019 ◽

Vol 12 (2) ◽

pp. 280 ◽

Cited By ~ 6

Author(s):

João Pacheco ◽

Jorge de Brito ◽

Carlos Chastre ◽

Luís Evangelista

Keyword(s):

Compressive Strength ◽

Conversion Factor ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Structural Behaviour ◽

Aggregate Concrete ◽

Coarse Aggregates ◽

Natural Aggregate ◽

Using Data ◽

The Relationship

This paper investigates the effect of recycled coarse aggregate incorporation on the relationship between 150 mm cubic and Փ 150 mm cylindrical compressive strength (the reference strength of standards) by comparing data from recycled and natural aggregate concrete compositions in which both cubes and cylinders were tested. A conversion factor from cubic to cylindrical strength is proposed in two versions: A deterministic and a probabilistic one. Such factor has not been studied before and researchers have been converting cubic data as if natural aggregate concrete were tested. The probabilistic factor is intended for reliability analyses on the structural behaviour of recycled aggregate concrete using data from laboratory cube tests. It was found that the incorporation of recycled coarse aggregates sourced from concrete waste significantly decreases the expected value of the factor but the factor’s scatter is relatively unaffected.

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Experimental Study on Compressive Strength of Recycled Aggregate Concrete with Different Replacement Ratios

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.174-177.1277 ◽

2012 ◽

Vol 174-177 ◽

pp. 1277-1280 ◽

Cited By ~ 2

Author(s):

Hai Yong Cai ◽

Min Zhang ◽

Ling Bo Dang

Keyword(s):

Experimental Study ◽

Compressive Strength ◽

Failure Mode ◽

Failure Process ◽

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Replacement Ratio ◽

Aggregate Concrete

Compressive strengths of recycled aggregate concrete(RAC) with different recycled aggregates(RA) replacement ratios at 7d, 28d, 60d ages are investigated respectively. Failure process and failure mode of RAC are analyzed, influences on compressive strength with same mix ratio and different RA replacement ratios are analyzed, and the reason is investigated in this paper. The experimental results indicate that compressive strength of recycled concrete at 28d age can reach the standard generally, it is feasible to mix concrete with recycled aggregates, compressive strength with 50% replacement ratio is relatively high.

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Internal Curing Effect and Compressive Strength Calculation of Recycled Clay Brick Aggregate Concrete

Materials ◽

10.3390/ma12111815 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1815

Author(s):

Feng Chen ◽

Kai Wu ◽

Lijian Ren ◽

Jianan Xu ◽

Huiming Zheng

Keyword(s):

Compressive Strength ◽

Recycled Aggregate Concrete ◽

Strength Calculation ◽

Internal Curing ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Clay Brick ◽

Significant Drop ◽

Aggregate Concrete ◽

Curing Age

In order to investigate the internal curing effect of recycled brick aggregate (RBA) in recycled aggregate concrete (RAC) and calculate its contribution to the final compressive strength, two RAC groups with different recycled aggregates and 6 replacement ratios (r) under 4 curing ages were tested. Results show that the compressive strengths of RACI and RACII decrease steadily with the increase of r when below 40%, and that there is a significant drop once the r is higher than 60%. The internal curing effect for RAC with a low RBA ratio is mainly reflected during the curing age of 14–21 days, while for RAC with a high RBA ratio, this internal curing effect appears earlier, during 7–14 days, and becomes very obvious after 14 days. In addition, the actual tested compressive strength of RAC replaced by 100% RBA exceeds around 40% of the expected compressive strength at the age of 28 days. When the age of RAC entirely with RBA is 28 days, the compressive strength caused by the internal curing effect accounts for around 28% of the actual tested compressive strength. The most appropriate r of RBA for RAC production is between 40% to 60%. Finally, the equations for calculating the compressive strength of RAC are presented considering the curing ages, the replacement ratios and the internal curing effect of RBA. Further, a unified equation is suggested for convenience in calculation.

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