scholarly journals Experimental Study on Mechanical Properties of Steel-Polyvinyl Alcohol Fibre-Reinforced Recycled Concrete

2021 ◽  
Vol 11 (22) ◽  
pp. 10550
Author(s):  
Haicheng Niu ◽  
Lei Wang ◽  
Jianhua Li ◽  
Jiakun Ji
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Polyvinyl Alcohol ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Test Results ◽  
Stress Strain Curve ◽  
Polyvinyl Alcohol Fibre ◽  
Alcohol Fibre ◽  
Uniaxial Compressive Stress

Research on the utilization of recycled concrete in civil engineering applications is gaining popularity world-wide due to the increased efforts to promote preservation of the environment and sustainable development. Recycled concrete is, however, presently still limited to nonstructural applications. This is due to the poor mechanical properties of recycled concrete, which make it difficult to cope with complex mechanical environments. Therefore, an experimental work is presented to investigate the mechanical behaviour of recycled concrete, focusing on the cube, flexural, and uniaxial compressive mechanical properties of steel-polyvinyl alcohol fibre-doped specimens. The test results showed that the compressive strength and the flexural strength of the recycled concrete increased by 6.0% and 55.2%, respectively, when steel fibre was single-incorporated. The cubic compressive strength of the recycled concrete decreased by 14.1% when polyvinyl alcohol fibre was single-incorporated, but there was a 47.9% increase in the flexural strength of recycled concrete. Based on these tests, the elastic modulus, the Poisson’s ratio, and the uniaxial compression toughness were digitised to derive mathematical expressions that provided a theoretical understanding of the mechanical properties of steel-polyvinyl alcohol fibre-reinforced recycled concrete. Moreover, combining the characteristics of the uniaxial compressive stress–strain curve of fibre-reinforced recycled concrete, an equation for the uniaxial compressive stress–strain curve of recycled concrete associated with the fibre characteristic value was established, which agreed well with the test results.

The Research of Test on Stress-Strain Constitutive Relations of Straw Concrete

2014 ◽  
Vol 584-586 ◽  
pp. 987-992
Author(s):  
Wei Liu ◽  
Wei Xi ◽  
Yi Lu Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Fly Ash ◽  
Constitutive Relations ◽  
Strain Curve ◽  
Green Building ◽  
Corn Straw ◽  
Stress Strain Curve ◽  
Stress Strain

As a new green building material, straw concrete are introduced about its mechanical properties and characteristics. Mechanical properties test such as prism compressive strength, elastic modulus and Poisson's ratios use standard prismatic blocks. Under different rate of corn straw, cement, sand and fly ash, test gets the full stress-strain curve. Results show that with increase of volume of corn straw, the prism compressive strength reduces significantly. Comparing with natural concrete, elastic modulus of straw concrete can reduces greatly. Poisson’s ratio reduces with increase of volume of corn straw. Fly ash could improve property of the material and replace cement, but excessive replacement will reduce the strength of material.

Evaluation of Microindentation Test Results Using FEM Simulations for the Determination of the Mechanical Properties of Various Ferrous or Non Ferrous Materials

2005 ◽  
Author(s):  
K.-D. Bouzakis ◽  
A. Lontos
Keyword(s):  
Mechanical Properties ◽  
Strain Curve ◽  
Constitutive Law ◽  
Test Results ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Analytical Methodology ◽  
Ball Diameter ◽  
Steel Balls

The determination of the mechanical properties using the nano or macroindentation test results was developed in order to predict the mechanical properties of materials such as thin or thick coatings [1]. In the present paper a new method using a continuous FEM supported simulation of the microindentation results through a special tester, is proposed in order to predict the stress–strain curve of various ferrous or non ferrous materials that are being used as constructive materials in several machines or devices. The elasticity modulus is determined using a large spherical indenter tip and the stress strain curve using smaller steel balls. In the case of three deferent ball diameter indenter tips, the adopted experimental-analytical methodology present similar results regarding the constitutive law of the examined steel or aluminum specimens.

scholarly journals Recycling of Foundry Sand Wastes in Self-Compacting Mortars: Use as Cementitious Materials and Fine Aggregates

2019 ◽  
Vol 9 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Ghania Sebki ◽  
Brahim Safi ◽  
Kahina Chahour
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Strain Curve ◽  
Physical And Mechanical Properties ◽  
Cementitious Materials ◽  
Fine Aggregate ◽  
Stress Strain Curve ◽  
Foundry Sand ◽  
Fine Aggregates

Abstract This work aims to study the possibility recycling of foundry sand wastes (FSW) as a cementations additive and fine aggregate in self-compacting mortars (SCM). For this, an experimental study was carried out to evaluate physical and mechanical properties of SCM. Firstly, sand is substituted by the foundry sand waste at dosages (0%, 10%, 30%, and 50%) by weight of the sand. Secondly cement is partially substituted by crushed foundry sand waste at different ratio (0%, 10%, 20%, 30%, and 50%) by weight of cement. The obtained results show that up to 50%, (FSW) can be used as fine aggregate for mortars without affecting the essential proprieties of mortar. However, beyond 50% of sand substitution, mortars lose their fluidity. The compressive strength of the mortars with 50% of cement substitution decreased compared to the control mortar. Value of the highest compressive strength recorded at 28 days, is of the order of 50 MPa for the mortar with 20% of cement substitution. Also, stress-strain curve show an acceptable mechanical behavior of FSW-based mortar at 50% of sand substitution.

scholarly journals Strength Assessment of Concrete using Rice Husk Ash, Polyvinyl Alcohol Fiber and Recycled Concrete Aggregate: A Critical Review

2021 ◽  
Vol 9 (VI) ◽  
pp. 723-730
Author(s):  
Satarupa Chakraborty
Keyword(s):  
Polyvinyl Alcohol ◽  
Rice Husk ◽  
Coarse Aggregate ◽  
Rice Husk Ash ◽  
Recycled Concrete ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Polyvinyl Alcohol Fibre ◽  
Alcohol Fibre

In this review study, the effect of three different materials such as rice husk ash, recycled concrete aggregate and Polyvinyl Alcohol fibre was reviewed in detail. Several past studies related to these material usage in strength enhancement of concrete was studied in detail. Rice husk ash is the ash which is mainly derived after burning the waste derived from the rice industry after the processing of rice. Recycled concrete aggregate is mainly the aggregate derived from the constructional waste. Polyvinyl Alcohol fibre is a special type of high strength fibre that is mainly used to improve the flexural strength and internal bonding of the concrete. Numerous studies were discussed in detail and depending upon the studies certain conclusion are drawn which are discussed further. Several studies related to the usage of rice husk ash conclude that the most optimum usage percentage of rice husk ash as partial replacement of ordinary Portland cement was at 10 percent usage. After 10 percent usage strength tends to decline. Results related o usage as partial replacement of natural fine aggregate that is sand showed that it can be used as partial replacement of natural coarse aggregate up to 20 percent and beyond that usage the strength was declining. The studies related to the usage of recycled concrete aggregate conclude that the most optimum percentage of usage of recycled concrete aggregate as partial replacement of natural coarse aggregate was 50 percent replacement and beyond this percentage the strength starts declining so therefore should not be used beyond that limit. Studies related to the usage of Polyvinyl Alcohol fibre revealed that the most optimum percentage of Polyvinyl Alcohol fibre was 1.5 percent and beyond this percentage both the compressive strength of concrete and flexural strength of concrete was declining. Test results concluded that Polyvinyl Alcohol fibre should be used up to 1.5 percent only.

Experimental Study on the Dynamic Compressive Mechanical Properties of Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 17-21 ◽  
Author(s):  
Ji Shu Sun ◽  
Yuan Ming Dou ◽  
Bo Li ◽  
Zhao Xia Chen
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Concrete Strength ◽  
Strain Curve ◽  
Plain Concrete ◽  
Stress Strain Curve ◽  
Growth Trend ◽  
Stress Strain ◽  
Compressive Strength Of Concrete

Dynamic compressive tests of plain concrete specimens (C30 and C40) are carried out on MTS, with the uniaxial strain rate ranging from 10-5/s to 10-2/s. The impacts of strain rates on concrete strength are studied systematically. The mechanical properties of compressive strength, elastic modulus and compressive stress-strain curve of concrete under different stain rates are also analyzed. The experiental relationships between strain rate and compressive strength of concrete are established. It is found that the compressive strength of concrete increases with the strain rate increasing. Modulus is also showing a growth trend, but the growth rate varies greatly; and the stress-strain curve under dynamic loads is similar to the one under static loads. These research achievements can provide us with a more accurate grasp of concrete actual working conditions and provide some guidance to structural design of concrete. These are important to build the dynamic damage constitutive models, too.

scholarly journals Influence of Carbonization Process on the Mechanical Properties of Nano-MgO Modified Cement Soil

2021 ◽  
Vol 13 (6) ◽  
pp. 3558
Author(s):  
Wei Wang ◽  
Hang Zhou ◽  
Jian Li ◽  
Feifei Tao ◽  
Cuihong Li ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Energy Dissipation ◽  
Dissipation Rate ◽  
Strain Curve ◽  
Energy Dissipation Rate ◽  
Peak Strain ◽  
Test Results ◽  
Stress Strain Curve ◽  
Strength Tests ◽  
Cement Soil

In order to explore the modification effect of carbonization time on nano-MgO-modified cement soil, unconfined compressive strength tests of nano-MgO-modified cement soil with carbonization times of 0 h, 6 h, 1 d, 2 d and 4 d were carried out. A method for normalizing the stress–strain curve was proposed, and the influence of nano-MgO content and carbonization time was investigated from the three aspects of compressive strength, peak strain and energy dissipation. The test results show the following: (1) The compressive strength of the modified cement soil can be significantly improved by adding 1.0% nano-MgO and after 1 d carbonization. (2) Under the same nano-MgO content, the peak strain of the modified cement soil after 2 d carbonization reaches the maximum, which can significantly increase its ductility. However, the nano-MgO content has little influence on the peak strain of the modified cement soil. (3) Under the same nano-MgO content, the energy dissipation rate of the modified cement soil after 1 d carbonization reaches the maximum, which can better resist the damage of external load.

scholarly journals Analysis of High Strength Concrete processed from Recycled Concrete Aggregates

2021 ◽  
Vol 9 (12) ◽  
pp. 1757-1763
Author(s):  
Shanu Sharma
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Strain Curve ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Stress Strain Curve ◽  
Stress Strain

Abstract: As everyone is aware of the fact that Natural Coarse Aggregate (NCA) is the main constituent of traditional concrete mixes. Whenever an existing concrete structure is demolished, it produces smashed concrete waste in the large amount. Concrete waste give rise to negative effects on the environment. To evade the environmental pollution and mark effective reuse of the concrete waste as Recycled Aggregates in the place of NCA. This operative initiative provides an opportunity to reduce air pollution and soil exploitation to some extent. Such concrete is sustainable in nature and also eco-friendly to the environment. Also, such waste material will lower the usage of naturally occurring stone to produce NCA and thus various natural energy resources will be safeguarded. This study covers the suitability norms for a material to be used for Recycled Aggregate. In this study the natural aggregate is replaced with recycled aggregate in the different percentages (0%, 25%, 50%). When percentage of recycled aggregate mixed in the fixed proportion as percentage replacement to natural aggregates, it imparts improvement in the property of fresh as well as hardened concrete like, compressive strength & split tensile strength. Laboratory results of this research indicates that the value of compressive strength, tensile strength stress-strain curve & NDT of these mixes drives on decreasing, but at the 25% replacement level, it achieves target mean strength. Hence, for the fundamental concrete mix Natural Coarse Aggregate can be efficiently replaced by the Recycled Aggregate to the range of 25%. Keywords: Concrete, Recycled aggregate, Natural Coarse Aggregate (NCA), Compressive Strength, Tensile strength, , NDT, Stress-Strain Curve

scholarly journals Discrete Element Simulation Analysis of Biaxial Mechanical Properties of Concrete with Large-Size Recycled Aggregate

2021 ◽  
Vol 13 (13) ◽  
pp. 7498
Author(s):  
Tan Li ◽  
Jianzhuang Xiao
Keyword(s):  
Mechanical Properties ◽  
Stress State ◽  
Strain Curve ◽  
Confining Pressure ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Model ◽  
Large Size

Concrete made with large-size recycled aggregates is a new kind of recycled concrete, where the size of the recycled aggregate used is 25–80 mm, which is generally three times that of conventional aggregate. Thus, its composition and mechanical properties are different from that of conventional recycled concrete and can be applied in large-volume structures. In this study, recycled aggregate generated in two stages with randomly distributed gravels and mortar was used to replace the conventional recycled aggregate model, to observe the internal stress state and cracking of the large-size recycled aggregate. This paper also investigated the mechanical properties, such as the compressive strength, crack morphology, and stress–strain curve, of concrete with large-size recycled aggregates under different confining pressures and recycled aggregate incorporation ratios. Through this research, it was found that when compared with conventional concrete, under the confining pressure, the strength of large-size recycled aggregate concrete did not decrease significantly at the same stress state, moreover, the stiffness was increased. Confining pressure has a significant influence on the strength of large-size recycled aggregate cocrete.

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