scholarly journals Studying the C–H Crystals and Mechanical Properties of Sustainable Concrete Containing Recycled Coarse Aggregate with Used Nano-Silica

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 122
Author(s):  
Shahriar Shahbazpanahi ◽  
Moslem Khalili Tajara ◽  
Rabar H. Faraj ◽  
Amir Mosavi
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Control Group ◽  
Nano Silica ◽  
Sustainable Concrete ◽  
Recycled Coarse Aggregate ◽  
The Third ◽  
Group Water ◽  
Control Samples

The present study aims to replace 30%, 40%, and 50% of the natural coarse aggregate (NCA) of concrete with recycled coarse aggregate containing used nano-silica (RCA-UNS) to produce a new sustainable concrete. Three groups of concrete are made and their mechanical properties and microstructure are studied. In the first group, which was the control group, normal concrete was used. In the second group, 30%, 40%, and 50% of the NCA were replaced with coarse aggregate obtained from crushed concrete of the control samples and with 0.5% nano-silica as filler. In the third group, 30%, 40%, and 50% of the concrete samples’ NCA were replaced with aggregates obtained from 90-day crushed samples of the second group. Water absorption, fresh concrete slump, and compressive strength of the three groups were investigated and compared through scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) tests. The results show that the third group’s compressive strengths increased by 12.8%, 10.9%, and 10% with replacing 30%, 40%, and 50% of NAC with RCA-NS at 28 days compared to the control samples, respectively. This could be due to the secondary production of calcium silicate hydrate due to the presence of new cement paste. The third group’s microstructure was also improved due to the change in the C–H and the production of extra C–S–H. Therefore, the hydration of cement with water produces C–H crystals while reactions are induced by recycled aggregate containing used nano-silica.

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 Mechanical Properties of Geopolymer Concrete Made With Partial Replacement of Coarse Aggregate by Recycled Aggregate

2019 ◽  
Vol 9 (1) ◽  
pp. 2301-2304 ◽  
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates

Construction is the one the fast growing field in the worldwide. There are many environmental issues connected with the manufacture of OPC, at the same time availability of natural coarse aggregate is getting reduced. Geopolymer binder and recycled aggregates are promising alternatives for OPC and natural coarse aggregates. It is produced by the chemical action of inorganic molecules and made up of Fly Ash, GGBS, fine aggregate, coarse aggregate and an alkaline solution of sodium hydroxide and sodium silicate. 10 M sodium hydroxide and sodium silicate alkali activators are used to synthesis the geopolymer in this study. Recycled aggregates are obtained from the construction demolished waste. The main focus of this work is to find out the mechanical properties of geopolymer concrete of grade G40 when natural coarse aggregate(NCA) is replaced by recycled coarse aggregate in various proportions such as 0%, 10%, 20%, 30%,40% and 50% and also to compare the results of geopolymer concrete made with recycled coarse aggregates(RAGPC) with geopolymer concrete of natural coarse aggregate(GPC) and controlled concrete manufactured with recycled aggregates(RAC) and controlled concrete of natural coarse aggregates(CC) of respective grade. It has been observed that the mechanical properties are enhanced in geopolymer concrete, both in natural coarse aggregate and recycled coarse aggregate up to 30% replacement when it is compared with the same grade of controlled concrete.

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.

Experimental Study on Strength and other Performance of Solid Concrete Bricks Made from Recycled Coarse Aggregate

2013 ◽  
Vol 357-360 ◽  
pp. 1212-1218 ◽  
Author(s):  
Xi Xi He ◽  
Tao Zhang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Flexural Strength ◽  
Physical Properties ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
The Impact ◽  
The Relationship

Recycled coarse aggregate solid concrete bricks were produced by QTY4-40 brick machine with strength grades of MU15-MU30. Compression and flexural strength of solid recycled coarse aggregate concrete brick were investigated. The impact of recycled aggregate on the solid concrete brick mechanical properties and physical properties was analyzed. The relationship between physical properties and strength, density was discussed.

scholarly journals Experimental Investigation on Self Compacting Concrete Using Recycled Aggregate

2021 ◽  
pp. 49-53
Author(s):  
N. Uday Kiran ◽  
S. Hanmanthu ◽  
C. Govardhan
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Experimental Work ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Self Compacting Concrete ◽  
Recycled Coarse Aggregate

In the present work, an experimental investigation was carried out on self-compacting concrete made with various replacement levels of recycled coarse aggregate. The main aim of the experimental work is to know the suitability and effects of recycled aggregates in SCC. Self-Compacting Concrete is a type of concrete which does not need any kind of vibration or compaction. In the present experimental work, the behaviour of concrete made with recycled aggregates is evaluated and compared with the traditional concrete in which the coarse aggregate is replaced with recycled aggregate by 0%, 50%, and 100% respectively. Mechanical properties of the concrete were evaluated in its fresh and hardened conditions.

Prediction of recycled coarse aggregate concrete mechanical properties using multiple linear regression and artificial neural network

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Suhas Vijay Patil ◽  
K. Balakrishna Rao ◽  
Gopinatha Nayak
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Artificial Neural Network ◽  
Prediction Model ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Training Phase ◽  
Content Type ◽  
Recycled Coarse Aggregate ◽  
Artificial Neural

Purpose Recycling construction waste is a promising way towards sustainable development in construction. Recycled aggregate (RA) is obtained from demolished concrete structures, laboratory crushed concrete, concrete waste at a ready mix concrete plant and the concrete made from RA is known as RA concrete. The purpose of this study is to apply multiple linear regressions (MLRs) and artificial neural network (ANN) to predict the mechanical properties, such as compressive strength (CS), flexural strength (FS) and split tensile strength (STS) of concrete at the age of 28 days curing made completely from the recycled coarse aggregate (RCA). Design/methodology/approach MLR and ANN are used to develop a prediction model. The model was developed in the training phase by using data from a previously published research study and a developed model was further tested by obtaining data from laboratory experiments. Findings ANN shows more accuracy than MLR with an R2-value of more than 0.8 in the training phase and 0.9 in a testing phase. The high R2-value indicates strong relation between the actual and predicted values of mechanical properties of RCA concrete. These models will help construction professionals to save their time and cost in predicting the mechanical properties of RCA concrete at 28 days of curing. Originality/value ANN with rectified linear unit transfer function and backpropagation algorithm for training is used to develop a prediction model. The outcome of this study is the prediction model for CS, FS and STS of concrete at 28 days of curing.

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