Experimental investigation of recycled aggregate effect on the concrete properties

2018 ◽  
Vol 9 (4) ◽  
pp. 560-571
Author(s):  
Hamed Hemmati Pourghashti ◽  
Malek Mohammad Ranjbar ◽  
Rahmat Madandoust
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Tensile Test ◽  
Recycled Concrete ◽  
Test Results ◽  
Content Type ◽  
Treatment Conditions ◽  
Natural Aggregates ◽  
Direct Tensile ◽  
Direct Tensile Test

Purpose The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples. Design/methodology/approach Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated. Findings According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength. Originality/value According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.

Size Effect on Mechanical Properties of LVL

2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Size Effect ◽  
Tensile Test ◽  
Compression Test ◽  
Test Results ◽  
Laminated Veneer Lumber ◽  
Object Of Study ◽  
The Relationship

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.

Comparison of Tensile Strengths with Different Test Methods in Ultra High Strength Steel-Fiber Reinforced Concrete (UHS-SFRC)

2009 ◽  
Vol 417-418 ◽  
pp. 649-652 ◽  
Author(s):  
Su Tae Kang ◽  
Jung Jun Park ◽  
Gum Sung Ryu ◽  
Gyung Taek Koh ◽  
Sung Wook Kim
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fiber Reinforced Concrete ◽  
Flexural Tensile Strength ◽  
Ultra High Strength Steel ◽  
Direct Tensile ◽  
Direct Tensile Test ◽  
Direct Tensile Strength

Ultra High Strength Steel-Fiber Reinforced Concrete (UHS-SFRC) is characterized by very high compressive and tensile strength that is about 8 times of ordinary concrete, and high ductility owing to the addition of steel fibers. This paper investigates the relationship existing among the direct tensile strength, flexural tensile strength and splitting tensile strength of UHS-SFRC. Differently from ordinary concrete, it is found that the first cracking strengths in UHS-SFRC obtained through direct tensile test and splitting tensile test are similar, while the strength obtained from flexural tensile test is significantly larger than those from other tests. Based on the experimental results, relationships between the direct tensile strength and flexural tensile strength, between the first cracking strengths in direct tensile test and in flexural tensile test, and between the first cracking strength in direct tensile test and the flexural tensile strength are proposed.

scholarly journals Enhancement of Energy Absorption Capacity of Polyethylene Fiber-Reinforced Cementitious Composites According to Admixtures and Curing Conditions

2020 ◽  
Vol 20 (1) ◽  
pp. 319-325
Author(s):  
Min-Jae Kim ◽  
Hong-Joon Choi ◽  
Booki Chun ◽  
Wonsik Shin ◽  
Doo-Yeol Yoo
Keyword(s):  
Compressive Strength ◽  
Tensile Test ◽  
Energy Absorption ◽  
Absorption Capacity ◽  
Limestone Powder ◽  
Cementitious Composites ◽  
Energy Absorption Capacity ◽  
Curing Conditions ◽  
Direct Tensile ◽  
Direct Tensile Test

This study aims to enhance the energy absorption capacity of cementitious composites with 2 vol.% of polyethylene fibers, by adjusting mixing ingredients and curing conditions. Ground blast furnace slag, cement kiln dust, limestone powder, and silica fume were incorporated, and two different curing conditions were applied: 72 h of curing at 90 ℃ and 120 h of curing at 40 ℃. Compressive strength test and direct tensile test were performed on 6 mixtures and the test results were compared with those of ultra-high-performance concrete and engineered cementitious composite specimens. The maximum compressive strength of the 6 mixtures was measured to be approximately 117 MPa. The higher cement replacement ratio of the other components resulted in a decrease in the compressive strength of the specimens cured at 90 ℃. In the direct tensile test, the specimens cured at 40 ℃ exhibited lower tensile strength than those cured at 90 ℃, but the strain capacity was increased by approximately 305% and reached 7.7%. This also resulted in an enhancement of the energy absorption capacity from 80%–292% because of the differences in micro-cracking and fracturing behaviors, such as an increase inthe number of micro-cracks and decrease in crack width.

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 A New Flattened Cylinder Specimen for Direct Tensile Test of Rock

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4157
Author(s):  
Qiuhua Rao ◽  
Zelin Liu ◽  
Chunde Ma ◽  
Wei Yi ◽  
Weibin Xie
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Cylindrical Specimen ◽  
Image Correlation ◽  
Stress Distributions ◽  
Direct Tension ◽  
Brazilian Disc ◽  
Indirect Tensile ◽  
Direct Tensile ◽  
Direct Tensile Test

In recent decades, researchers have paid more attention to the indirect tensile test than to the direct tensile test (DTT) of rocks, mainly due to difficulties in the alignment and the stress concentration at the end of an intact cylindrical specimen. In this paper, a new flattened cylinder specimen and a clamp device were designed to obtain the true tensile strength of the rock in DTT. Stress distributions of the specimen with different lengths (l) and cutting thicknesses (t) were analyzed, and damage processes of the specimen were monitored by the Digital Image Correlation (DIC), the fractured sections were also scanned. Different mechanical parameters were also obtained by the DTT of the flattened cylinder specimens and the intact cylinder specimens, as well as the Brazilian disc. Research results show that the tensile strength obtained by DTT is smaller than the Brazilian disc and is slightly greater than the intact cylindrical specimen. The flattened cylinder specimen with 0.20 ≤ 2t/D < 0.68 and 0.10 ≤ l/D ≤ 0.20 is recommended to measure the true tensile strength of rock material in DTT. This new shape of the specimen is promising to be extended in the uniaxial or triaxial direct tension test.

scholarly journals Calculation Derivation and Test Verification of Indirect Tensile Strength of Asphalt Pavement Interlayers at Low Temperatures

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6041
Author(s):  
Qian Zhang ◽  
Zhihe Fang ◽  
Yiheng Xu ◽  
Zhao Ma
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Asphalt Pavement ◽  
Indirect Tensile Strength ◽  
Elastic Theory ◽  
Calculation Formula ◽  
Indirect Tensile Test ◽  
Indirect Tensile ◽  
Direct Tensile ◽  
Direct Tensile Test

When the direct tensile test is adopted to determine the interlayer tensile strength of the asphalt pavements, specimen separation or internal cracking often occurs at the bonding area of the loading head, rather than at the interlaminar bonding interface. In view of the tedious and discrete data of the direct tensile test, this paper attempts to introduce an indirect tensile test to determine the interlayer bond strength of asphalt pavement to solve this problem. However, the indirect tensile test method of a binder lacks the corresponding mechanical theory. This paper deduces the calculation formula of the indirect tensile strength of a binder based on elastic theory. A mechanical model of the test was established with the finite element method. In accordance with the two-dimensional elastic theory and the Flamant solution, an analytical solution of tensile stress in the indirect tensile test is proposed through the stress superposition. On this basis, the calculation formula for the indirect tensile strength of the interlaminar bonding is derived according to Tresca’s law. A low-temperature indirect tensile test was designed and conducted to verify the correctness of the formula. By comparing the results of the indirect tensile test and direct tensile test, it is found that the interlaminar strength of the mixture measured by them is similar, and the dispersion of indirect tensile test results is small. The results show that the indirect tensile test can replace the direct tensile test to evaluate the interlaminar tensile strength.

Variasi Penambahan Sika Cim Dan Fiber Kawat Pada Beton Mutu Fc’ 30 Mpa

2018 ◽  
Vol 9 (2) ◽  
pp. 67-73
Author(s):  
M Zainul Arifin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Curing Temperature ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Normal Concrete ◽  
Astm Method ◽  
Additive Type ◽  
Composition Variation ◽  
Compressive Strength Of Concrete

This research was conducted to determine the value of the highest compressive strength from the ratio of normal concrete to normal concrete plus additive types of Sika Cim with a composition variation of 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1 , 50% and 1.75% of the weight of cement besides that in this study also aims to find the highest tensile strength from the ratio of normal concrete to normal concrete in the mixture of sika cim composition at the highest compressive strength above and after that added fiber wire with a size diameter of 1 mm in length 100 mm with a ratio of 1% of material weight. The concrete mix plan was calculated using the ASTM method, the matrial composition of the normal concrete mixture as follows, 314 kg / m3 cement, 789 kg / m3 sand, 1125 kg / m3 gravel and 189 liters / m3 of water at 10 cm slump, then normal concrete added variations of the composition of sika cim 0.25%, 0.50%, 0.75%, 1.00%, 1.25%, 1.5%, 1.75% by weight of cement and fiber, the tests carried out were compressive strength of concrete and tensile strength of concrete, normal maintenance is soaked in fresh water for 28 days at 30oC. From the test results it was found that the normal concrete compressive strength at the age of 28 days was fc1 30 Mpa, the variation in the addition of the sika cim additive type mineral was achieved in composition 0.75% of the cement weight of fc1 40.2 Mpa 30C. Besides that the tensile strength test results were 28 days old with the addition of 1% fiber wire mineral to the weight of the material at a curing temperature of 30oC of 7.5%.

scholarly journals Physical, Deformation, and Stiffness Properties of Recycled Concrete Aggregate

2021 ◽  
Vol 13 (8) ◽  
pp. 4245
Author(s):  
Katarzyna Gabryś ◽  
Emil Soból ◽  
Wojciech Sas
Keyword(s):  
Recycled Concrete ◽  
Experimental Program ◽  
Concrete Aggregate ◽  
Test Results ◽  
Recycled Concrete Aggregate ◽  
Granulometric Analysis ◽  
Stiffness Properties ◽  
Grain Distribution ◽  
Natural Aggregates ◽  
Critical Reduction

The construction sector is currently struggling with the reuse of waste originating from the demolition and modernization of buildings and roads. Furthermore, old buildings are gradually being replaced by new structures. This brings a significant increase of concrete debris to waste landfills. To prevent this, many studies on the possibilities of recycling concrete, known as recycled concrete aggregate (RCA), have been done. To broaden the applicability of reused concrete, an understanding of its properties and engineering behavior is required. A difficulty in sustainable, proper management of RCA is the shortage of appropriate test results necessary to assess its utility. For this reason, in the present study, the physical, deformation, and stiffness properties of RCA with gravely grain distribution were analyzed carefully in the geotechnical laboratory. To examine the mentioned properties, an extensive experimental program was planned, which included the following studies: granulometric analysis, Proctor and oedometer tests, as well as resonant column tests. The obtained research results show that RCA has lower values of deformation and stiffness parameters than natural aggregates. However, after applying in oedometer apparatus repetitive cycles of loading/unloading/reloading, some significant improvement in the values of the parameters studied was noticed, most likely due to susceptibility to static compaction. Moreover, some critical reduction in the range of linear response of RCA to dynamic loading was observed.

Improving the structural performance of reinforced geopolymer concrete incorporated with hazardous heavy metal waste ash

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Suresh Kumar Arunachalam ◽  
Muthukannan Muthiah ◽  
Kanniga Devi Rangaswamy ◽  
Arunkumar Kadarkarai ◽  
Chithambar Ganesh Arunasankar
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Medical Waste ◽  
Source Material ◽  
Geopolymer Concrete ◽  
Deformation Capacity ◽  
Cement Concrete ◽  
Content Type ◽  
Load Carrying ◽  
Reinforced Cement

Purpose Demand for Geopolymer concrete (GPC) has increased recently because of its many benefits, including being environmentally sustainable, extremely tolerant to high temperature and chemical attacks in more dangerous environments. Like standard concrete, GPC also has low tensile strength and deformation capacity. This paper aims to analyse the utilization of incinerated bio-medical waste ash (IBWA) combined with ground granulated blast furnace slag (GGBS) in reinforced GPC beams and columns. Medical waste was produced in the health-care industry, specifically in hospitals and diagnostic laboratories. GGBS is a form of industrial waste generated by steel factories. The best option to address global warming is to reduce the consumption of Portland cement production and promote other types of cement that were not a pollutant to the environment. Therefore, the replacement in ordinary Portland cement construction with GPC is a promising way of reducing carbon dioxide emissions. GPC was produced due to an alkali-activated polymeric reaction between alumina-silicate source materials and unreacted aggregates and other materials. Industrial pollutants such as fly ash and slag were used as raw materials. Design/methodology/approach Laboratory experiments were performed on three different proportions (reinforced cement concrete [RCC], 100% GGBS as an aluminosilicate source material in reinforced geopolymer concrete [GRGPC] and 30% replacement of IBWA as an aluminosilicate source material for GGBS in reinforced geopolymer concrete [IGRGPC]). The cubes and cylinders for these proportions were tested to find their compressive strength and split tensile strength. In addition, beams (deflection factor, ductility factor, flexural strength, degradation of stiffness and toughness index) and columns (load-carrying ability, stress-strain behaviour and load-deflection behaviours) of reinforced geopolymer concrete (RGPC) were studied. Findings As shown by the results, compared to Reinforced Cement Concrete (RCC) and 100% GGBS based Reinforced Geopolymer Concrete (GRGPC), 30% IBWA and 70% GGBS based Reinforced Geopolymer Concrete (IGRGPC) (30% IBWA–70% GGBS reinforced geo-polymer concrete) cubes, cylinders, beams and columns exhibit high compressive strength, tensile strength, flexural strength, load-carrying ability, ultimate strength, stiffness, ductility and deformation capacity. Originality/value All the results were based on the experiments done in this research. All the result values obtained in this research are higher than the theoretical values.

Effect of using magnetic water on the mechanical properties of concrete exposed to elevated temperature

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wasim Barham ◽  
Ammar AL-Maabreh ◽  
Omar Latayfeh
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elevated Temperature ◽  
Flexural Strength ◽  
Tap Water ◽  
Splitting Tensile Strength ◽  
Content Type ◽  
Normal Water ◽  
Magnetic Water

PurposeThe influence of using magnetic water instead of tap water in the mechanical properties of the concrete exposed to elevated temperatures was investigated. Two concrete mixes were used and cast with the same ingredients. Tap water was used in the first mix and magnetic water was used in the second mix. A total of 48 specimens were cast and divided as follows: 16 cylinders for the concrete compressive strength test (8 samples for each mix), 16 cylinders for the splitting tensile strength (8 specimens for each mix) and 16 beams to test the influences of magnetized water on the flexural strength of concrete (8 specimens for each mixture). Specimens were exposed to temperatures of (25 °C, 200 °C, 400 °C and 600 °C). The experimental results showed that magnetic water highly affected the mechanical properties of concrete. Specimens cast and curried out with magnetic water show higher compressive strength, splitting tensile strength and flexural strength compared to normal water specimens at all temperatures. The relative strength range between the two types of water used was 110–123% for compressive strength and 110–133% for splitting strength. For the center point loading test, the relative flexural strength range was 118–140%. The use of magnetic water in mixing concrete contribute to a more complete hydration process.Design/methodology/approachExperimental study was carried out on two concrete mixes to investigate the effect of magnetic water. Mix#1 used normal water as the mixing water, and Mix#2 used magnetic water instead of normal water. After 28 days, all the samples were taken out of the tank and left to dry for seven days, then they were divided into different groups. Each group was exposed to a different temperature where it was placed in a large oven for two hours. Three different tests were carried out on the samples, these tests were concrete compressive strength, flexural strength and splitting tensile strength.FindingsExposure of concrete to high temperatures had a significant influence on concrete mechanical properties. Specimens prepared using magnetic water showed higher compressive strength at all temperature levels. The use of magnetic water in casting and curing concrete can increase the compressive strength by 23%. Specimens prepared using magnetic water show higher splitting tensile strength at all temperatures up to 33%. The use of magnetic water in casting and curing can strengthen and increase concrete resistance to high temperatures, a significant enhancement in flexural strength at all temperatures was found with a value up to 40%.Originality/valuePrevious research proved the advantages of using magnetic water for improving the mechanical properties of concrete under normal conditions. The potential of using magnetic water in the concrete industry in the future requires conducting extensive research to study the behavior of magnetized concrete under severe conditions to which concrete structures may be subjected to. These days, there are attempts to obtain stronger concrete with high resistance to harsh environmental conditions without adding new costly ingredients to its main mixture. No research has been carried out to investigate the effect of magnetic water on the mechanical properties of concrete exposed to elevated temperature. The main objective of this study is to evaluate the effect of using magnetic water on the mechanical properties of hardened concrete subjected to elevated temperature.

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