scholarly journals A COMPARISON OF TESTING METHODS FOR DETERMINATION OF SPRAYED CONCRETE TENSILE STRENGTH

2019 ◽  
Vol 23 ◽  
pp. 54-57
Author(s):  
Martin Závacký
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Construction Material ◽  
Common Reason ◽  
Bending Moments ◽  
Testing Methods ◽  
Sprayed Concrete ◽  
Pure Tension ◽  
Splitting Tensile Test

Sprayed concrete is important construction material in tunnelling. Primary lining is essential in NATM where the sprayed concrete can be loaded by tension due to bending moments. The tension is common reason of failure because concrete has a relatively low tensile strength. The tensile strength is usually determined by splitting tensile test in laboratory. However, the results can be distorted because the specimen is not loaded by pure tension in this case. The paper compares results of concrete tensile strength determined by two methods: indirect by the splitting tensile test and direct by the modified tensile test.

scholarly journals Determination of the Material Properties of the Reinforcement for Textile-Reinforced Concrete Elements

2021 ◽  
Author(s):  
Sergej Rempel ◽  
Marcus Ricker ◽  
Tânia Feiri
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Tensile Test ◽  
Material Properties ◽  
Construction Material ◽  
Gumbel Distribution ◽  
Mean Value ◽  
Elastic Behaviour ◽  
Textile Reinforced Concrete ◽  
Design Values

Abstract Textile-reinforced concrete has emerged in recent years as a new and valuable construction material. The design of textile-reinforced concrete requires knowledge on the mechanical properties of different textile types as well as their reinforcing behaviour under different loading conditions. Conventional load-bearing tests tend to be complex, time-consuming, costly and can even lack consistent specifications. To mitigate such drawbacks, a standardised tensile test for fibre strands was developed aiming at characterising the material properties needed for the design of a textile-reinforced concrete component. For the sake of this study, an epoxy resin-soaked AR-glass reinforcement was considered. The standardised tensile test uses a fibre strand with 160 mm length, which shall be cut out of a textile grid. The results show that the textile reinforcement has a linear-elastic behaviour, and the ultimate tensile strength can be statistically modelled by a Gumbel distribution. Furthermore, the results indicate that the modulus of elasticity is not influenced by the length or the number of fibre strands. Therefore, the mean value from the standardised test can be used for the design purpose. These findings are essential to derive an appropriate partial safety factor for the calculation of the design values of the tensile strength and can be used to determine the failure probability of textile-reinforced concrete components.

scholarly journals Early-Age Strength Measurement of Shotcrete

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Abbas Mohajerani ◽  
Daniel Rodrigues ◽  
Christian Ricciuti ◽  
Christopher Wilson
Keyword(s):  
Current Practice ◽  
Construction Material ◽  
Mining Industry ◽  
Early Age ◽  
Testing Methods ◽  
Strength Measurement ◽  
Sprayed Concrete ◽  
Ground Support ◽  
Strength Tests

Shotcrete or sprayed concrete is a special concrete designed for spraying onto a surface, as a construction material. With shotcrete application as a ground support system ever-present in both mining and tunnelling sectors, a major requirement of drive progression is to determine when it is safe to reenter beneath freshly sprayed concrete. Accurately determining this time is of paramount importance. Generally, this reentry time is based on measuring the developing strength of shotcrete until an adequate strength value is reached. The issue with current practice is that there is no widely accepted or generally preferred method that accurately assesses the shotcrete lining’s true early-age strength. However, there are a number of strength tests that are commercially available and used in the industry; these include the soil penetrometer, needle penetrometer, bolt screws, beam end testers, and drilled core samples. This paper researches into these testing methods and their characteristics in order to determine their accuracy, testing ranges, and suitability for in situ use in the tunnelling and mining industry. The investigation ultimately reveals that current methods all have substantial shortcomings. Based on these findings, recommendations are proposed for the applicable use of the current testing methods and recommendations for future improvements.

scholarly journals Tensile Behavior of Self-Compacting Steel Fiber Reinforced Concrete Evaluated by Different Test Methods

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 251
Author(s):  
Xinxin Ding ◽  
Changyong Li ◽  
Minglei Zhao ◽  
Jie Li ◽  
Haibin Geng ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Tensile Test ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Axial Tensile ◽  
Splitting Tensile Test

Due to the mechanical properties related closely to the distribution of steel fibers in concrete matrix, the assessment of tensile strength of self-compacting steel fiber reinforced concrete (SFRC) is significant for the engineering application. In this paper, seven groups of self-compacting SFRC were produced with the mix proportion designed by using the steel fiber-aggregates skeleton packing test method. The hooked-end steel fibers with length of 25.1 mm, 29.8 mm and 34.8 mm were used, and the volume fraction varied from 0.4% to 1.4%. The axial tensile test of notched sectional prism specimen and the splitting tensile test of cube specimen were carried out. Results show that the axial tensile strength was higher than the splitting tensile strength for the same self-compacting SFRC, the axial tensile work and toughness was not related to the length of steel fiber. Finally, the equations for the prediction of tensile strength of self-compacting SFRC are proposed considering the fiber distribution and fiber factor, and the adaptability of splitting tensile test for self-compacting SFRC is discussed.

scholarly journals Stochastic approach for the material properties of reinforcing textiles for the design of concrete members

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sergej Rempel ◽  
Marcus Ricker ◽  
Tânia Feiri
Keyword(s):  
Tensile Strength ◽  
Reinforced Concrete ◽  
Tensile Test ◽  
Material Properties ◽  
Construction Material ◽  
Gumbel Distribution ◽  
Stochastic Approach ◽  
Elastic Behaviour ◽  
Textile Reinforced Concrete ◽  
Concrete Members

AbstractTextile-reinforced concrete has emerged in recent years as a new and valuable construction material. The design of textile-reinforced concrete requires knowledge on the mechanical properties of different textile types as well as their reinforcing behaviour under different loading conditions. Conventional load-bearing tests tend to be complex, time-consuming, costly and can even lack consistent specifications. To mitigate such drawbacks, a standardised tensile test for fibre strands was used to characterise the material properties needed for the design of a textile-reinforced concrete member. The standardised tensile test uses a fibre strand with 160 mm length, which is cut out of a textile grid. For the sake of this study, an epoxy resin-soaked AR-glass reinforcement was considered. The results show that the textile reinforcement has a linear-elastic behaviour, and the ultimate tensile strength can be statistically modelled by a Gumbel distribution. Furthermore, the results indicate that the modulus of elasticity is not influenced by the length or the number of fibre strands. Therefore, the mean value attained from the standardised test can be used for design purposes. These findings are essential to derive an appropriate partial safety factor for the calculation of the design values of the tensile strength and can be used to determine the failure probability of textile-reinforced concrete members.

scholarly journals The Effect of Pumice Sand as Fine Aggregate on Tensile Strength of Precast Concrete

2021 ◽  
Vol 328 ◽  
pp. 10013
Author(s):  
Abd. Majid Abdullah ◽  
Abdul Gaus ◽  
Mufti Amir Sultan
Keyword(s):  
Tensile Strength ◽  
Tensile Test ◽  
Precast Concrete ◽  
Testing Machine ◽  
Maximum Load ◽  
Splitting Tensile Strength ◽  
The Other ◽  
Fine Aggregate ◽  
Splitting Tensile Test ◽  
Test Objects

In this study, a cylinder with a size of 15 cm x 30 cm totaling 10 pieces for the splitting tensile test. 5 pieces cylinder were used for the normal splitting tensile test and the other 5 pieces cylinder were used for the joint splitting tensile test were used. Two tests have been carried out, namely the normal splitting tensile strength (control) and the joint splitting tensile strength. In testing the tensile strength of the test object, the applied tool to provide the load is the Compression Testing Machine. The splitting tensile strength test was carried out on 10 test objects in the form of concrete cylinders with an age of 28 days. 5 test objects were used in the normal splitting tensile strength (control). Meanwhile, the other 5 test objects were used in the joint splitting tensile strength. The test objects were given the load gradually until the test objects experienced cracks or reaching maximum load.

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