Experimental investigation and comparative machine-learning prediction of compressive strength of recycled aggregate concrete

2021 ◽  
Vol 25 (2) ◽  
pp. 919-932 ◽  
Author(s):  
S. Reza Salimbahrami ◽  
Reza Shakeri
Keyword(s):  
Machine Learning ◽  
Experimental Investigation ◽  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete

scholarly journals Mixture Optimization of Recycled Aggregate Concrete Using Hybrid Machine Learning Model

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4331
Author(s):  
Itzel Nunez ◽  
Afshin Marani ◽  
Moncef L. Nehdi
Keyword(s):  
Machine Learning ◽  
Compressive Strength ◽  
Regression Trees ◽  
Mixture Design ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Gradient Boosting ◽  
Environmental Footprint ◽  
Aggregate Concrete

Recycled aggregate concrete (RAC) contributes to mitigating the depletion of natural aggregates, alleviating the carbon footprint of concrete construction, and averting the landfilling of colossal amounts of construction and demolition waste. However, complexities in the mixture optimization of RAC due to the variability of recycled aggregates and lack of accuracy in estimating its compressive strength require novel and sophisticated techniques. This paper aims at developing state-of-the-art machine learning models to predict the RAC compressive strength and optimize its mixture design. Results show that the developed models including Gaussian processes, deep learning, and gradient boosting regression achieved robust predictive performance, with the gradient boosting regression trees yielding highest prediction accuracy. Furthermore, a particle swarm optimization coupled with gradient boosting regression trees model was developed to optimize the mixture design of RAC for various compressive strength classes. The hybrid model achieved cost-saving RAC mixture designs with lower environmental footprint for different target compressive strength classes. The model could be further harvested to achieve sustainable concrete with optimal recycled aggregate content, least cost, and least environmental footprint.

Predicting Compressive Strength of Recycled Aggregate Concrete by Multiple Regression Analysis

2012 ◽  
Vol 253-255 ◽  
pp. 546-549 ◽  
Author(s):  
Yoon Seok Shin ◽  
Gwang Hee Kim
Keyword(s):  
Compressive Strength ◽  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Construction Industry ◽  
Multiple Regression Model ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Average Error ◽  
Aggregate Concrete

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.

Experimental Study on Compressive Strength of Recycled Aggregate Concrete

2008 ◽  
Vol 385-387 ◽  
pp. 381-384 ◽  
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.

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

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.

Quality Improvement of Recycled Aggregate Concrete

2006 ◽  
Vol 302-303 ◽  
pp. 308-313 ◽  
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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