scholarly journals Scale Effect in Direct Shear Tests on Recycled Concrete Aggregate

2015 ◽  
Vol 37 (2) ◽  
pp. 45-49 ◽  
Author(s):  
Emil Soból ◽  
Wojciech Sas ◽  
Alojzy Szymański
Keyword(s):  
Mechanical Properties ◽  
Moisture Content ◽  
Optimum Moisture Content ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Direct Shear ◽  
Recycled Concrete Aggregate ◽  
Shear Tests ◽  
Direct Shear Tests ◽  
Shear Box

Abstract The depletion of natural resources is forcing researchers to explore the possibilities of new aggregates, such as recycled concrete aggregate (RCA). In this article, the mechanical properties and the influence of the size of the direct shear box on the obtained parameters were examined. The study was conducted in two apparatus: medium (120 × 120 mm) and large (250 × 250 mm). In each of these devices, a total of 6 tests were performed: 3 for dry sample and 3 at optimum moisture content. From the results, the conclusions described below have been drawn

scholarly journals Roller Compacted Concrete with Recycled Concrete Aggregate for Paving Bases

2020 ◽  
Vol 12 (8) ◽  
pp. 3154 ◽  
Author(s):  
Hedelvan Emerson Fardin ◽  
Adriana Goulart dos Santos
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Modulus Of Elasticity ◽  
Splitting Tensile Strength ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Roller Compacted Concrete ◽  
Flexural Tensile Strength ◽  
Mechanical And Physical Properties

This research aimed to investigate the mechanical and physical properties of Roller Compacted Concrete (RCC) used with Recycled Concrete Aggregate (RCA) as a replacement for natural coarse aggregate. The maximum dry density method was adopted to prepare RCC mixtures with 200 kg/m³ of cement content and coarse natural aggregates in the concrete mixture. Four RCC mixtures were produced from different RCA incorporation ratios (0%, 5%, 15%, and 30%). The compaction test, compressive strength, splitting tensile strength, flexural tensile strength, and modulus of elasticity, porosity, density, and water absorption tests were performed to analyze the mechanical and physical properties of the mixtures. One-way Analysis of Variance (ANOVA) was used to identify the influences of RCA on RCC’s mechanical properties. As RCA increased in mixtures, some mechanical properties were observed to decrease, such as modulus of elasticity, but the same was not observed in the splitting tensile strength. All RCCs displayed compressive strength greater than 15.0 MPa at 28 days, splitting tensile strength above 1.9 MPa, flexural tensile strength above 2.9 MPa, and modulus of elasticity above 19.0 GPa. According to Brazilian standards, the RCA added to RCC could be used for base layers.

scholarly journals Recycled Concrete Aggregate for Medium-Quality Structural Concrete

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4612
Author(s):  
Dong Viet Phuong Tran ◽  
Abbas Allawi ◽  
Amjad Albayati ◽  
Thi Nguyen Cao ◽  
Ayman El-Zohairy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Pulse Velocity ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Predictive Equation ◽  
Recycled Concrete Aggregate ◽  
Structural Concrete ◽  
Medium Quality ◽  
Ultrasound Pulse

This paper reports an evaluation of the properties of medium-quality concrete incorporating recycled coarse aggregate (RCA). Concrete specimens were prepared with various percentages of the RCA (25%, 50%, 75%, and 100%). The workability, mechanical properties, and durability in terms of abrasion of cured concrete were examined at different ages. The results reveal insignificant differences between the recycled concrete (RC) and reference concrete in terms of the mechanical and durability-related measurements. Meanwhile, the workability of the RC reduced vastly since the replacement of the RCA reached 75% and 100%. The ultrasound pulse velocity (UPV) results greatly depend on the porosity of concrete and the RC exhibited higher porosity than that of the reference concrete, particularly at the transition zone between the RCA and the new paste. Therefore, the sound transmission in the RC required longer times than that in the reference concrete. Moreover, a predictive equation relating the compressive strength to the UPV was developed.

scholarly journals Influence of different monomer ratios and recycled concrete aggregate on mechanical properties and durability of geopolymer concretes

2019 ◽  
Vol 205 ◽  
pp. 519-528 ◽  
Author(s):  
Mahdi Koushkbaghi ◽  
Pedram Alipour ◽  
Behzad Tahmouresi ◽  
Ehsan Mohseni ◽  
Ashkan Saradar ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate

Large Scale Laboratory Direct Shear Tests on Ice

1975 ◽  
Vol 12 (2) ◽  
pp. 169-178 ◽  
Author(s):  
W. D. Roggensack
Keyword(s):  
Large Scale ◽  
Stress Conditions ◽  
Direct Shear ◽  
Shear Tests ◽  
Principal Stresses ◽  
Lake Ice ◽  
Direct Shear Tests ◽  
Strength Determination ◽  
Crystal Diameter ◽  
Shear Box

This paper presents the results of a series of large scale direct shear tests performed on lake ice. Test specimens were oriented with the principal stresses acting in the plane of the ice sheet, approximately normal to the long axes of the columnar crystals. Sample dimensions were large in comparison with mean crystal diameter, reducing the possibility of deviations introduced by size effects. Although a number of assumptions are made concerning stress conditions at failure, results for uniform, artificially ‘seeded’ test pond ice indicate a failure mechanism that is frictional and consistent with triaxial test data reported elsewhere. Post-peak shear resulted in the formation of a distinct failure zone that also displayed a frictional response. The direct shear test described is robust and simple, does not require elaborate sample preparation, and may present an alternative method of strength determination for ice mechanics problems where the shear box configuration duplicates field stress conditions and constraints.

Research on Mixture Ratio of Recycled Concrete Aggregate in Concrete

2012 ◽  
Vol 193-194 ◽  
pp. 1371-1375
Author(s):  
Yong San Cheng ◽  
Ke Qiang Yu ◽  
Shuang Xi Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Raw Materials ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Mixture Ratio

In order to better understand the recycled concrete aggregate, it is essential to investigate the different mixture ratio in it. For determining the better mixture ratio of recycled concrete aggregate, the experimental investigation was conducted by making use of recycled concrete aggregate of different ratio instead of small stones in concrete, while maintaining the proportion of other raw materials of concrete unchanged. Its mechanical properties were also investigated. It is found that the better materials proportion of recycled concrete is that sand: recycled aggregate: water= 1: 1.8 : 2.1: 0.55.

Development of Mechanical Properties of Cement Based Composites with Recycled Concrete Aggregate

2016 ◽  
Vol 825 ◽  
pp. 11-14
Author(s):  
Jaromír Hrůza ◽  
Jaroslav Topič ◽  
Lukáš Hlubocký ◽  
Tomáš Plachý
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Concrete Structures ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Dynamic Young’S Modulus ◽  
Dynamic Young's Modulus

This article deals with the usage of recycled concrete, which arises from demolitions of concrete structures. The aim is to find out what amount of recycled concrete as a binder influences final mechanical properties of the concrete. It was found that the gradual replacement of cement with recycled concrete causes reduction of the dynamic Young’s modulus and decreases the size of the increase in strength during the first 28 days. Overall, it is confirmed that recycled concrete may be used for concrete structures with regard to their purpose, importance and applicability.

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