scholarly journals Mechanical Performance of Recycled Aggregate Concrete Containing Lathe Waste Steel Fibre

2021 ◽  
Vol 17 (4) ◽  
pp. 306-311
Author(s):  
S.A. Alabi ◽  
C. Arum
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Building Materials ◽  
Steel Fibre ◽  
Mechanical Performance ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Aggregate Concrete

The increasing demand, diminishing supplies, and growing pressure on natural resources have necessitated recycling and reusing waste. Several kinds of research have been done on the reuse and recycling of debris from building projects. Thus, with a view to the reuse of waste materials, the elimination of environmental contamination, the reduction of overhead costs of concrete, and the extension of the service life of concrete structures, this research aimed to study the feasibility of utilizing recycled concrete aggregate (RCA) with constant inclusion of waste steel fibre (LWSF) in concrete by evaluating its workability, compressive and splitting tensile strengths. A concrete mix ratio of 1:2:4 by weight of cement, sand, and granite was adopted with a water-cement ratio of 0.45. Five different concrete mixes were prepared in this study; one normal aggregate concrete (NAC) and four (4) other mixes with 25%, 50%, 75%, and 100% recycled aggregate content with a constant 1.5% addition of LWSF. The result of workability shows a reduction with an increase in the percentage replacement level. The recycled aggregate concrete (RAC) was characterized by lower compressive strength as compared with the NAC. When the replacement ratio increased from 25% to 50%, a significant reduction of about 14% and 30% were observed in the compressive strength at 7-days, but at 28-days slight increase in the compressive strength was observed. Also, a decrease in splitting tensile strength as the percentage replacement of crushed granite (CG) with RCA is increased was observed. Overall, the findings showed that the RAC-containing LWSF is environmentally sustainable and would significantly reduce the global greenhouse impact and building materials' overall quality. Keywords: Recycled concrete, lathe waste, steel fibre, compressive strength, tensile strength

scholarly journals Performance of Recycled Aggregate Concrete for M25 Grade Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 4694-4700
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Inorganic Particles ◽  
Natural Aggregates

Recycled aggregates (RCA) are the aggregates which are made up of crushed, inorganic particles that are obtained from the construction demolition debris. Now a day’s protection of environment is the ultimate challenge to the society. So the usage of RCA’s is the best alternative for the aggregates which are obtained naturally in the construction activity. The scope of using these recycled concrete aggregates is increasing day by day. It reduces the cost effectively as we are using waste concrete as recycled aggregates. The main focus of this paper is to use find the strength qualities of recycled aggregates so as to use it as an alternative for the natural aggregates in high strength concrete for various construction activities. Comparison of workability, compressive strength, tensile strength, elastic modulus and flexural strength of recycled aggregate concrete is made with natural aggregate concrete. Here M25 grade concrete is taken and the natural aggregates were replaced with recycled aggregates in various percentages of 0%, 25%, 50%, 75% and 100%. The mix design for these replacement ratios are done by using code of IS 10262-2009. In order to determine the properties which were mentioned above a total of 60 cubes, 10 beams and 40 cylinders were casted. The compressive strength and tensile strength of RCA concrete have been determined for 7 days and 28 days where as the modulus of elasticity and the flexural strength of RCA concrete are determined after curing for the period of 28 days. The tests done on RCA concrete are compared with concrete which is obtained by natural aggregates As per IS codification the parameters which were determined are reducing moderately as the amount of aggregates which are recycled is being raised

scholarly journals Experimental study on mechanical properties and microstructures of steel fiber-reinforced fly ash-metakaolin geopolymer-recycled concrete

2021 ◽  
Vol 60 (1) ◽  
pp. 578-590
Author(s):  
Zhong Xu ◽  
Zhenpu Huang ◽  
Changjiang Liu ◽  
Xiaowei Deng ◽  
David Hui ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Steel Fiber ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Mix Proportion ◽  
Optimal Mix

Abstract Geopolymer cementitious materials and recycled aggregate are typical representatives of material innovation research in the engineering field. In this study, we experimentally investigated a method to improve the performance of geopolymer-recycled aggregate concrete (GRAC). The recycled concrete aggregates and steel fiber (SF), fly ash (FA), metakaolin (MK), and sodium silicate solution were used as the main raw materials to prepare fiber-reinforced geopolymer-recycled aggregate concrete (FRGRAC). First, the orthogonal test was carried out to study the GRAC, and the optimal mix proportion was found. Second, building on the optimal mix proportion, the effects of the SF content on the slump, 7 and 28 days compressive strength, tensile strength, and flexural strength of FRGRAC were further studied. Finally, the microscopic mechanism of FRGRAC was studied by scanning electron microscopy (SEM). The study results indicate that the slump continues to decrease as the fiber content increases, but the compressive strength, tensile strength, and flexural strength increase to a certain extent. Through SEM analysis, it is found that SF restrains the development of cracks and improves the strength of concrete.

scholarly journals Compressive Strength of Concrete with Recycled Concrete Aggregate as Coarse Aggregate and Recycled Paving Block Aggregate as Fine Aggregate Partially Substituted by Recycled Brick Aggregate

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Idi Priyono ◽  
Meiske Widyarti, Erizal
Keyword(s):  
Compressive Strength ◽  
Residential Buildings ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Concrete Mix

An excessive extraction of natural resources for aggregate in concrete mix can caused an environmental degradation.  According to Indonesia ministry of industry in 2017, the use of cement is predicted will reach 84,96 million tons, that can affected the use of aggregate for concrete mix are quadruplet to 250 – 350 million tons. Opimally, the use of recycled material is green method that can reduce an excessive extraction of natural aggregates and keep an environmental sustain. The aim of this study is to obtain recycled aggregate concrete compressive strength and examine recycled aggregate concrete quality in days 3, 7, 28, 35, and 90 along with a proposal of the use of recycled aggregate concrete as a building construction material. This research used experimental method of SNI 03-2834-2002 the standard of normal concrete mix design for f’c 25 MPa then built five types of concrete mix of REC B, REC C, REC D, REC E, and REC F with every types of concrete has four sample are used for compressive strength test. The fine recycled paving block aggregate (RPA) were used partially to substituted a fine recycled brick aggregate (RBA) at 0%, 25%, 50%, 75%, and 100% by weigth. The result of this study showed the mixed concrete REC D with RCA 100%, RPA 50% and RBA 50% in 28 days is generate highest compressive strength than other recycle aggregates concrete mixes. Compressive strength at 28 days in a mix codes REC B, REC C, REC D, REC E and REC F are 18,12 MPa; 18,36 MPa; 19,35 MPa;16,69 MPa; and 16,39 MPa. The results show that it is feasible to replace a natural aggregate entirely by recycled aggregates. With compressive strength over 17 MPa at 28 days, mix codes REC B, REC C and REC D are recommended to use the recycled aggregate concrete for structure of residential buildings but mix codes REC E and REC F aren’t recommended and only allowed for non-structural concrete such as separate wall (SNI 8140:2016). Based on SNI 03-0691-1996 about solid brick concrete (paving block), recycle aggregate concrete with mix code of REC B, REC C, and REC D are able to use on paving block with B quality such as parking lot. While, recycled aggregate concrete with mix code of REC E and REC F are able to use on paving block with C and D quality which used for pedestrian, garden and other use. 

scholarly journals Laboratory Investigation on the Shrinkage Cracking of Waste Fiber-Reinforced Recycled Aggregate Concrete

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1196 ◽  
Author(s):  
Xiaoxin Wu ◽  
Jinghai Zhou ◽  
Tianbei Kang ◽  
Fengchi Wang ◽  
Xiangqun Ding ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fiber Reinforced ◽  
Shrinkage Cracking ◽  
Aggregate Concrete

This paper aims to study the effectiveness of adding waste polypropylene fibers into recycled aggregate concrete (RAC) on shrinkage cracking. The influences of fiber properties (length and content) on the shrinkage performance of RAC are investigated. Firstly, through the plat-ring-type shrinkage test and free shrinkage test, both of the early age and long-term shrinkage performance of waste fiber recycled concrete (WFRC) were measured. Then, X-ray industrial computed tomography (ICT) was carried out to reflect the internal porosity changes of RAC with different lengths and contents of fibers. Furthermore, the compressive strength and flexural strength tests are conducted to evaluate the mechanical performance. The test results indicated that the addition of waste fibers played an important role in improving the crack resistance performance of the investigated RAC specimens as well as controlling their shrinkage behaviour. The initial cracking time, amount and width of cracks and shrinkage rate of fiber-reinforced specimens were better than those of the non-fiber-reinforced specimen. The addition of waste fibers at a small volume fraction in recycled concrete had not obviously changed the porosity, but it changed the law of pore size distribution. Meanwhile, the addition of waste fibers had no significant effect on the compressive strength of RAC, but it enhanced the flexural strength by 43%. The specimens reinforced by 19-mm and 0.12% (volume fraction) waste fibers had the optimal performance of cracking resistance.

scholarly journals Microstructure and Mechanical Properties of Recycled Aggregate Concrete in Seawater Environment

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Pengjun Yue ◽  
Zhuoying Tan ◽  
Zhiying Guo
Keyword(s):  
Compressive Strength ◽  
Chloride Penetration ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Aggregate Concrete ◽  
Basic Properties ◽  
Seawater Corrosion ◽  
Theoretical And Numerical Analysis

This study aims to conduct research about the microstructure and basic properties of recycled aggregate concrete under seawater corrosion. Concrete specimens were fabricated and tested with different replacement percentages of 0%, 30%, and 60% after immersing in seawater for 4, 8, 12, and 16 months, respectively. The basic properties of recycled aggregate concrete (RAC) including the compressive strength, the elastic modulus, and chloride penetration depth were explicitly investigated. And the microstructure of recycled concrete aggregate (RCA) was revealed to find the seawater corrosion by using scanning electron microscope (SEM). The results showed that higher amount of the RCA means more porosity and less strength, which could lower both the compressive strength and resistance to chloride penetration. This research could be a guide in theoretical and numerical analysis for the design of RAC structures.

scholarly journals Utilisation of Recycled Aggregate as Coarse Aggregate in Concrete

2009 ◽  
Vol 1 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Yong P.C. ◽  
Teo D.C.L
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Normal Concrete ◽  
Aggregate Concrete

In this rapid industrialised world, recycling construction material plays an important role to preserve the natural resources. In this research, recycled concrete aggregates (RCA) from site-tested concrete specimens were used. These consist of 28-days concrete cubes after compression test obtained from a local construction site. These concrete cubes are crushed to suitable size and reused as recycled coarse aggregate. The amount of recycled concrete aggregate used in this research is approximately 200 kg. Many researchers state that recycled aggregates are only suitable for non-structural concrete application. This research, however, shows that the recycled aggregates that are obtained from site-tested concrete specimen make good quality concrete. The compressive strength of recycled aggregate concrete (RAC) is found to be higher than the compressive strength of normal concrete. Recycled aggregate concrete is in close proximity to normal concrete in terms of split tensile strength, flexural strength and wet density. The slump of recycled aggregate concrete is low and that can be improved by using saturated surface dry (SSD) coarse aggregate.

Recycling of Waste Concrete and Fly Ash for Recycled Aggregate Concrete: Fundamental Characteristics Evaluation

2009 ◽  
Vol 620-622 ◽  
pp. 255-258 ◽  
Author(s):  
Cheol Woo Park
Keyword(s):  
Fly Ash ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Recycled Concrete Aggregate ◽  
Aggregate Concrete ◽  
Waste Concrete

As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.

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.

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

2012 ◽  
Vol 174-177 ◽  
pp. 1277-1280 ◽  
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.

Shear strength of reinforced concrete beams with recycled aggregates

2019 ◽  
Vol 22 (8) ◽  
pp. 1938-1951 ◽  
Author(s):  
George Wardeh ◽  
Elhem Ghorbel
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Strain Softening ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Opening Displacement ◽  
Aggregate Concrete ◽  
Natural Aggregate ◽  
Hinge Model

This article presents an experimental program on the shear behavior of beams without transversal reinforcement manufactured with natural aggregate concrete and 100% recycled aggregate concrete. The beams were tested under four-point bending for a shear span-to-depth ratio ( a/ d) equal to 1.5 and 3.0. The mechanical properties of two mixes were characterized in terms of compressive strength, splitting tensile strength, and elastic modulus. Three-point bending tests were performed on plain pre-notched samples in order to determine the fracture properties by an inverse analysis of experimental force–crack mouth opening displacement curves using the analytical nonlinear hinge model and a power law strain-softening relationship. The strain-softening law is described by two parameters being, respectively, the power n and the critical crack opening displacement wc. The experimental results show that, for the same class of compressive strength, tensile strength, fracture energy, and the shear strength of recycled aggregate concrete are lower than natural aggregate concrete. The decrease in the fracture energy and the shear strength is consistent with the decrease in the splitting tensile strength of the recycled aggregate concrete mixes compared to the natural aggregate concrete. Critical shear crack theory was adopted to model the shear behavior of beams tested with a/ d = 3.0. For an accurate evaluation of the deformation capacity of tested beams, the nonlinear hinge model for recycled concrete members was extended to recycled concrete sections. For deep beams ( a/ d = 1.5), the strut-and-tie model was used. Finally, comparisons of prediction models to a wide range of experimental data are presented.

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