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 Drilled Core Specimen Testing Method for Determination of Tensile Strength Values of Rock Materials

2018 ◽  
Author(s):  
Eren Komurlu ◽  
Serhat Demir
Keyword(s):  
Tensile Strength ◽  
Failure Load ◽  
Experimental Studies ◽  
Drill Hole ◽  
Uniaxial Tensile ◽  
Drilling Process ◽  
Uniaxial Tensile Strength ◽  
Drill Bits ◽  
Uniaxial Tensile Stress ◽  
Direct Tensile

In this study, a new direct tensile strength determination method of drilled core specimen testing was investigated with numerical and experimental studies. Effect of different drill diameters of holes of the rock specimens was analysed to assess the ideal drill-hole design. The aim of drilling process is decreasing the failure load and stress concentration at the adhesive part to prevent invalid failures. Drilled specimens were determined to fail due to the start of cracking under the condition of uniaxial tensile stress distribution at sidewalls of holes. It was found that drill bits with the diameter of 11 mm is usable for a practical specimen drilling process to make a significant decrease in the failure load of the core specimens with the NX size (@54 mm) diameter. According to the results obtained from numerical and experimental analyses, an equation was suggested to determine uniaxial tensile strength values of drilled core specimens with the hole diameter of 11 mm.

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.

Experimental Research on Tensile Strength of Premixed Concrete at Early Ages

2014 ◽  
Vol 556-562 ◽  
pp. 687-691 ◽  
Author(s):  
Xiao Fen Li ◽  
Ping Ren
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Exact Results ◽  
Direct Tension ◽  
Splitting Strength ◽  
Experimental Apparatus ◽  
Structural Applications ◽  
Direct Tensile ◽  
Direct Tensile Strength ◽  
The Relationship

The splitting tensile method for the tensile strength of concrete is usually used in structural applications, so it is great important in the investigating the relation between the direct tensile strength and the splitting strength. But the relationship between the splitting strength and the direct tensile strength is not consolidatly confirmed at home and abroad. In order to obtain the exact results, the experimental apparatus for concrete of the direct tension are designed, which resolves the difficulty of ensuring that the load is truly axial. Tests of the direct tension are performanced on three different concrete mixes (C20,C40,C60) at 3, 7, 14 , 28 and 60 days and the test data do not scatter. The relations between the tensile strength and the cube compressive strength are obtained and a formula for investigating the relation between the direct tensile strength and the splitting strength are proposed.

Influence of Concrete Strength Grade and Age on Three Tensile Strengths

2012 ◽  
Vol 450-451 ◽  
pp. 179-186
Author(s):  
Xi Xi He ◽  
Ping Fang
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Concrete Strength ◽  
Test Methods ◽  
Uniaxial Tensile ◽  
Strength Parameters ◽  
Uniaxial Tensile Strength ◽  
Fly Ash Concrete ◽  
Direct Tensile ◽  
Direct Tensile Strength

Uniaxial tensile strength is one of the important strength parameters of concrete. In this study, two test methods were applied to determine direct tensile strength, splitting tensile strength and flexural strength of fly ash concrete specimens with the same cross section and different strength grades. Relationship among the uniaxial tensile, splitting tensile and flexural strength of concrete were researched. Furthermore, the influence of concrete strength and age to the three tensile strengths were specifically analyzed in the paper.

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