scholarly journals EFFECT OF HYBRID FIBER ON THE MECHANICAL PROPERTIES OF RECYCLED AGGREGATE CONCRETE

2018 ◽  
Vol 80 (5) ◽  
Author(s):  
Sallehan Ismail ◽  
Mahyuddin Ramli
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Strength ◽  
Impact Load ◽  
Load Resistance ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Normal Concrete ◽  
Aggregate Concrete

This study investigates the effect of inclusion of polyolefin and polypropylene fibers at various volume fractions in single and hybrid forms on the mechanical properties of recycled aggregate concrete (RAC) mix that consists of treated coarse recycled concrete aggregate (RCA). Testing parameters, such as compressive strength, flexural strength, static modulus of elasticity, and impact load resistance, are utilized to evaluate the mechanical strength of specimens. The various properties of the modified RAC are also analyzed and compared with those of normal concrete and unmodified RAC specimens. Findings indicate that the mechanical strength properties of RAC mixture using treated RCA were significantly enhanced by adding fibers. The overall optimized mechanical strength results could be obtained in RAC mixtures with fiber in hybrid form, where their compressive strength at long-term curing age, can be significantly improved by 7% upto 11% higher than normal concrete. In addition, RAC mix with hybrid fibers produced the highest flexural strength and impact load resistance by an increase of 5% and 175%, respectively as compared with the control concrete.  

EFFECT OF DIFFERENT TYPES OF FIBER UTILIZATION ON MECHANICAL PROPERTIES OF RECYCLED AGGREGATE CONCRETE CONTAINING SILICA FUME

2020 ◽  
Vol 15 (1) ◽  
pp. 119-136 ◽  
Author(s):  
Muhammet Gökhan Altun ◽  
Meral Oltulu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Steel Fiber ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Hybrid Fibers ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Volume Fractions ◽  
Coarse Aggregates

ABSTRACT The use of recycled aggregate (RA) instead of natural aggregate (NA) in concrete is necessary for environmental protection and the effective utilization of resources. The addition of recycled aggregates in concrete increases shrinkage, porosity and decreases the mechanical properties compared to that of normal concrete. This study was aimed at investigating how the addition of various proportions of polypropylene and steel fiber affect the mechanical properties of recycled aggregate concrete (RAC). The natural coarse aggregates (NCAs) used in the production of normal concrete (NC) were replaced in 30% and 50% proportions by recycled coarse aggregates (RCAs) obtained from the demolished buildings. In this case, a polypropylene fiber (PF) content of 0.1% and steel fiber (SF) 1% and 2% volume fractions were used, along with hybrid fibers-a combination of the two. While the material performance of RAC compared to NC is analyzed by reviewing existing published literature, it is not evident what the use of RCAs and hybrid fibers have on the mechanical properties of concrete. The results showed that the compressive strength, flexural strength and impcat resistance of RAC were reduced as the percentage of RCAs increased. It was observed that the compressive strength was increased with the addition of 1% steel fiber in the RAC. The flexural and impact performance of steel fiber-reinforced concrete (Specimens NC and RAC) was increased as the volume fractions of steel fiber increased. The hybrid fiber reinforced concretes showed the best results in their mechanical performance of all the concrete groups.

The Compressive Strength and Flexural Strength Test of Recycled Pebble Aggregate Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 1433-1436
Author(s):  
Zong Ping Chen ◽  
Chun Heng Zhou ◽  
Pei Huan Ye
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Test Results ◽  
Replacement Rate ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Damage Process

Primary concrete of pebble coarse aggregate were used as the source of recycled aggregate concrete for pebble recycled coarse aggregate. Replacement rate of recycled aggregate for change parameter, 99 specimens were designed. The prism compressive strength, cube compressive strength and flexural strength were tested and achieved. The test results show that damage process and form of pebble coarse aggregate concrete are similar to those of normal concrete. It is gel adhesive failure between coarse aggregate and cement. Comparing with natural aggregate concrete, the strength indexes of recycled aggregate concrete of pebble coarse Aggregate slightly increase.

Relationship between Microstructure and Mechanical Properties for Recycled Aggregate Concrete

2013 ◽  
Vol 811 ◽  
pp. 213-217
Author(s):  
Wei Li ◽  
Wen Sheng Ding ◽  
Hai Ying Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Average Pore ◽  
Aggregate Concrete ◽  
Active Particles ◽  
Lower Porosity ◽  
Porous Microstructure ◽  
Mixing Method

Microstructure is an important factor that influences the mechanical properties of recycled aggregate concrete (RAC). This paper was devoted to an investigation of the relationship between mechanical properties and porosity, hydrate, microstructure of interfacial transition zone (ITZ) in RAC. The result showed that mechanical properties of RAC can be further enhanced with lower porosity, and there was a good linear relation, whereas it did not exist between compressive strength of RAC and average pore diameter. Fine active particles and the hydrate were formed into the cracked and loose layer of ITZ in RAC by A tripe mixing method (TM). Through SEM observation, it is expected that the compressive strength of the RAC can be improved by modifying the porous microstructure and hydrate in ITZ.

scholarly journals Basic Mechanical Properties of Basalt Fiber Reinforced Recycled Aggregate Concrete

2017 ◽  
Vol 11 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Huaxin Liu ◽  
Jianwei Yang ◽  
Xiangqing Kong ◽  
Xuxu Xue
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Basalt Fiber ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mixing Ratio ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Chopped Basalt Fiber

In order to study the basic mechanical properties of basalt fiber reinforced recycled aggregate concrete, the concrete mix ratio, the length and the volume mixing ratio of chopped basalt fiber yarn are designed for changing factors. A total of 324 specimens have been completed for this investigation. The compressive strength, splitting tensile strength, elastic modulus and axial compressive strength of basalt fiber recycled concrete have carried on the experimental study and theoretical analysis as 81 specimens, respectively. In all specimens, coarse aggregate were replaced by recycled aggregate with a replacement rate of 100%. Experimental results show that the failure process and failure pattern of basalt fiber recycled concrete and ordinary concrete are similar; With the improvement of concrete strength grade; When the volume mixing ratio of chopped basalt fiber yarn is 0.2%, the mechanic performance can effectively improve, and the length of chopped basalt fiber has less effect on the mechanical indexes; The conversion relation between common concrete mechanics index is no longer suitable for basalt fiber recycled concrete, new conversion formulas for basalt fiber recycled concrete between the mechanics index were presented through fitting experimental data.

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 Mechanical Properties of Recycled Aggregate Concrete at Low and High Water/Binder Ratios

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Gai-Fei Peng ◽  
Yan-Zhu Huang ◽  
Hai-Sheng Wang ◽  
Jiu-Feng Zhang ◽  
Qi-Bing Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fracture Energy ◽  
Main Type ◽  
High Water ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Heating Process ◽  
Aggregate Concrete

This paper presents an experimental research on mechanical properties of recycled aggregate concrete (RAC) at low and high water/binder (W/B) ratios. Concrete at two W/B ratios (0.255 and 0.586) was broken into recycled concrete aggregates (RCA). A type of thermal treatment was employed to remove mortar attached to RCA. The RAC at a certain (low or high) W/B ratio was prepared with RCA made from demolished concrete of the same W/B ratio. Tests were conducted on aggregate to measure water absorption and crushing values and on both RAC and natural aggregate concrete (NAC) to measure compressive strength, tensile splitting strength, and fracture energy. The mechanical properties of RAC were lower than those of NAC at an identical mix proportion. Moreover, the heating process caused a decrease in compressive strength and fracture energy in the case of low W/B ratio but caused an increase in those properties in the case of high W/B ratio. The main type of flaw in RCA from concrete at a low W/B ratio should be microcracks in gravel, and the main type of flaw in RCA from concrete at a high W/B ratio should be attached mortar.

scholarly journals Experimental study on the influence of recycled aggregates on the mechanical properties of concrete

2021 ◽  
Vol 283 ◽  
pp. 01033
Author(s):  
Chuangui Li ◽  
Hongkui Zhao ◽  
Jianfeng Wu ◽  
Xiangang Li ◽  
Ya Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Solid Waste ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Cohesive Force ◽  
Recycled Aggregates ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Splitting Strength

Construction solid waste has become an important environmental pollution source in the city, and the treatment and application of construction solid waste has become the focus of attention. Construction waste recycled aggregates have defects such as high water absorption and micro cracks, which affect its extensive application. In order to improve the utilization rate of recycled aggregates, the influence of different replacement rates of recycled aggregates on the mechanical properties of concrete is studied in this paper. The results show that with the increase of replacement rate of recycled aggregates, the 3-day, 7-day and 28-day compressive strength, splitting strength and cohesive force of concrete decrease gradually, but the mechanical properties of concrete decrease slowly at 3 days and 7 days, and decrease obviously at 28 days. Moreover, with the increase of replacement rate of recycled aggregates, the decline trend of mechanical properties is not obvious. Compared with natural aggregate concrete, the 28-day compressive strength, splitting strength and cohesive force of 100% recycled aggregate concrete are reduced by 16.1%, 20.1% and 18.1% respectively, but the mechanical properties meet the requirements of C30 concrete, which provides a reference for engineering application.

scholarly journals Compressive Mechanical Properties of a Novel Recycled Aggregate Concrete with Recycled Lightweight Aggregate

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Anjun Li ◽  
Gaoqiang Zhou ◽  
Xianggang Zhang ◽  
Ercong Meng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Lightweight Aggregate ◽  
Ultimate Strain ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Peak Strain ◽  
Replacement Ratio ◽  
Stress Strain ◽  
Aggregate Concrete

A novel recycled aggregate concrete was prepared by replacing the natural aggregate with recycled lightweight aggregate. Subsequently, the mechanical properties and compressive stress-strain constitutive relation of the recycled lightweight aggregate concrete (RLWAC) were explored. For this purpose, the recycled lightweight aggregate (RLWA) replacement ratio (0%, 25%, 50%, 75%, and 100%) was selected as a variable, and the compressive strength of 15 cube and 30 prism specimens was evaluated. The failure morphology of the specimen was subsequently characterized, along with the cubic compressive strength, axial compressive strength, peak strain, ultimate strain, and other performance indices. The influence of the replacement ratio for the specimen indices of the RLWAC was also analyzed. It was observed that the dry apparent density of RLWAC decreased gradually on increasing the replacement ratio. Compared with 0% replacement ratio, a decrease of 6.50%, 11.39%, 21.84%, and 27.54% was observed, respectively. On enhancing the RLWA replacement ratio, the compressive strength, peak strain, and ultimate strain of RLWAC were observed to be gradually reduced. As the replacement ratio was increased from 75% to 100%, the peak strain was noted to decrease the most by about 6.8%. As the replacement ratio was increased from 50% to 75%, the ultimate strain decreased the most by about 14.2%. Based on the experimental findings, the functional relationships of the strength indices and the conversion value of each strength index with the replacement ratio were also established. Finally, based on the model proposed by the existing model, the stress-strain equation of RLWAC was developed, and the fitting results were observed to be in good agreement with the test results.

Mechanical Properties and Permeability of Previous Color Recycled Aggregate Concrete

2014 ◽  
Vol 665 ◽  
pp. 221-224
Author(s):  
Ping Hua Zhu ◽  
Xin Xin Zhang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Flexural Strength ◽  
Permeability Coefficient ◽  
Polypropylene Fiber ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Cube Strength

Experimental study was carried out on compressive cube strength, flexural strength and permeability coefficient of color permeable concrete using concrete waste as coarse recycled aggregate. The results show that watercement ratio has significant effect on compressive cube strength, flexural strength and permeability coefficient of color permeable recycled aggregate concrete (RAC).The flexural strength of RAC is improved by polypropylene fiber. The content of pigment from 5% to 10% has no impact on mechanical properties and permeability of RAC.

scholarly journals Recycled Aggregates Concrete Compressive Strength Prediction Using Artificial Neural Networks (ANNs)

2021 ◽  
Vol 6 (2) ◽  
pp. 17
Author(s):  
Mohamad Ali Ridho B K A ◽  
Chayut Ngamkhanong ◽  
Yubin Wu ◽  
Sakdirat Kaewunruen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Strength Prediction ◽  
Concrete Compressive Strength ◽  
Conventional Concrete ◽  
Aggregate Concrete ◽  
Ann Models

The recycled aggregate is an alternative with great potential to replace the conventional concrete alongside with other benefits such as minimising the usage of natural resources in exploitation to produce new conventional concrete. Eventually, this will lead to reducing the construction waste, carbon footprints and energy consumption. This paper aims to study the recycled aggregate concrete compressive strength using Artificial Neural Network (ANN) which has been proven to be a powerful tool for use in predicting the mechanical properties of concrete. Three different ANN models where 1 hidden layer with 50 number of neurons, 2 hidden layers with (50 10) number of neurons and 2 hidden layers (modified activation function) with (60 3) number of neurons are constructed with the aid of Levenberg-Marquardt (LM) algorithm, trained and tested using 1030 datasets collected from related literature. The 8 input parameters such as cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, fine aggregate, and age are used in training the ANN models. The number of hidden layers, number of neurons and type of algorithm affect the prediction accuracy. The predicted recycled aggregates compressive strength shows the compositions of the admixtures such as binders, water–cement ratio and blast furnace–fly ash ratio greatly affect the recycled aggregates mechanical properties. The results show that the compressive strength prediction of the recycled aggregate concrete is predictable with a very high accuracy using the proposed ANN-based model. The proposed ANN-based model can be used further for optimising the proportion of waste material and other ingredients for different targets of concrete compressive strength.

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