Test Method for Direct Tensile Strength of Intact Rock Core Specimens

2020 ◽  
Author(s):  
Keyword(s):  
Tensile Strength ◽  
Intact Rock ◽  
Test Method ◽  
Direct Tensile ◽  
Direct Tensile Strength

scholarly journals Determination of Direct Tensile Strength Values of Rock Materials by a New Test Method of Drilled Disc Tension

2019 ◽  
Author(s):  
Eren Komurlu ◽  
Serhat Demir
Keyword(s):  
Tensile Strength ◽  
Experimental Studies ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Direct Tension ◽  
Rock Materials ◽  
Uniaxial Tensile Stress ◽  
Direct Tensile ◽  
Drill Holes ◽  
Direct Tensile Strength

Use of drilled disc specimens was investigated with both numerical and experimental studies to determine direct tensile strengths of rock materials. A new loading apparatus with rods to insert into the drill holes of discs has been designed and manufactured to supply tension by using the compression test presses. In addition to the use of popular compressive presses for direct tension, elimination of the gluing in the standard direct tensile strength test method is a significant advantage to make possible both hard and soft rocks to be tested. The Brazilian test discs with the diameter of NX size and length to diameter ratio of 0.5 were used in tests. Different loading apparatus designs were analyzed and ideal angle of contact between rock and the loading rods was assessed to be 50° within various choices investigated in this study. The drilled discs were determined to fail due to the crack initiation under the condition of uniaxial tensile stress distribution at sidewalls of the hole. In addition to the drilled disc tension test, standard direct tensile strength tests were also carried out to take as reference and compare the results obtained from different methods. According to the results of both numerical and experimental studies, an equation was suggested to determine uniaxial tensile strengths of drilled disc specimens with 20 mm hole diameter and the contact angle of 50°.

scholarly journals Study on Characteristics of Tensile Strength of Concrete Considering Temperature Dependence in Mass Concrete Structures

2018 ◽  
Vol 199 ◽  
pp. 11012
Author(s):  
Hiroki Izumi ◽  
Juniti Arai ◽  
Toshiaki Mizobuchi
Keyword(s):  
Tensile Strength ◽  
Thermal Properties ◽  
Thermal Stress ◽  
Thermal Cracking ◽  
Splitting Tensile Strength ◽  
Test Method ◽  
Temperature History ◽  
Concrete Member ◽  
Direct Tensile ◽  
Direct Tensile Strength

It is important to grasp mechanical and thermal properties in order to verify the possibility of thermal cracking. In this study, for the purpose of improving the accuracy of analysis in prediction of cracking caused by thermal stress, it was investigated that the direct tensile strength and thermal properties considering temperature history inside concrete member may be applied as a design values for the analysis of prediction of cracking caused by thermal stress. From results of these experiments, in early age, the direct tensile strength under mass curing which is considered temperature history inside concrete member is higher than the splitting tensile strength under standard curing. Which is cured under water of 20°C. However, the direct tensile strength under mass curing is lower than the splitting tensile strength under standard curing after 7 days. At 28 days, the strength of former was about 20% lower than that of latter. In this study, the estimated formula on the strength development of the direct tensile strength was proposed. And the thermal expansion coefficient was estimated using measured values of strain and temperature. In this paper, it was reported that the test method of direct tensile strength considering temperature history inside concrete member was proposed and that the accuracy of analysis for the prediction of thermal cracking by using this method would be improved.

scholarly journals IX. On the existence of an element of strength in beams subjected to transverse strain, arising from the lateral action of the fibres or particles on each other, and named by the author the 'resistance of flexture.’

1855 ◽  
Vol 145 ◽  
pp. 225-242
Keyword(s):  
Tensile Strength ◽  
Cast Iron ◽  
Neutral Axis ◽  
Direct Compression ◽  
Transverse Strain ◽  
Direct Tension ◽  
Direct Tensile ◽  
Direct Tensile Strength

It has been long known, that under the existing theory of beams, which recognizes only two elements of strength, namely, the resistances to direct compression and extension, the strength of a bar of cast iron subjected to transverse strain cannot be reconciled with the results obtained from experiments on direct tension, if the neutral axis is in the centre of the bar. The experiments made both on the transverse and on the direct tensile strength of this material have been so numerous and so carefully conducted, as to admit of no doubt of their accuracy; and it results from them, either that the neutral axis must be at, or above, the top of the beam, or there must be some other cause for the strength exhibited by the beam when subjected to transverse strain.

scholarly journals Tensile Behavior Characteristics of High-Performance Slurry-Infiltrated Fiber-Reinforced Cementitious Composite with Respect to Fiber Volume Fraction

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3335 ◽  
Author(s):  
Seungwon Kim ◽  
Dong Joo Kim ◽  
Sung-Wook Kim ◽  
Cheolwoo Park
Keyword(s):  
Tensile Strength ◽  
Energy Absorption ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Absorption Capacity ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Energy Absorption Capacity ◽  
Direct Tensile ◽  
Direct Tensile Strength

Concrete has high compressive strength, but low tensile strength, bending strength, toughness, low resistance to cracking, and brittle fracture characteristics. To overcome these problems, fiber-reinforced concrete, in which the strength of concrete is improved by inserting fibers, is being used. Recently, high-performance fiber-reinforced cementitious composites (HPFRCCs) have been extensively researched. The disadvantages of conventional concrete such as low tensile stress, strain capacity, and energy absorption capacity, have been overcome using HPFRCCs, but they have a weakness in that the fiber reinforcement has only 2% fiber volume fraction. In this study, slurry infiltrated fiber reinforced cementitious composites (SIFRCCs), which can maximize the fiber volume fraction (up to 8%), was developed, and an experimental study on the tensile behavior of SIFRCCs with varying fiber volume fractions (4%, 5%, and 6%) was carried out through direct tensile tests. The results showed that the specimen with high fiber volume fraction exhibited high direct tensile strength and improved brittleness. As per the results, the direct tensile strength is approximately 15.5 MPa, and the energy absorption capacity was excellent. Furthermore, the bridging effect of steel fibers induced strain hardening behavior and multiple cracks, which increased the direct tensile strength and energy absorption capacity.

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