scholarly journals Comparative Study on the Fatigue Behaviour of SCC and VC

2014 ◽  
Vol 627 ◽  
pp. 333-336 ◽  
Author(s):  
Sara Korte ◽  
Veerle Boel ◽  
Wouter de Corte ◽  
Geert de Schutter
Keyword(s):  
Crack Width ◽  
Static Load ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Self Compacting Concrete ◽  
Irreversible Damage ◽  
Bending Tests ◽  
Loading Rates ◽  
Four Point Bending ◽  
Concrete Type

Continuous cyclic loading on concrete constructions involves a progressive cracking mechanism, leading to significant changes of the material properties during the lifetime of the structure. Gradually, irreversible damage is inflicted and the carrying capacity is affected, which may cause structural collapse at a stress or strain level much lower than in case of a single static load. This so-called fatigue phenomenon is well-documented in literature for traditional, vibrated concrete (VC), but this is not the case for self-compacting concrete (SCC). Given the fact that this latter concrete type is already used worldwide in many types of structures, including cyclically loaded ones, a good knowledge and understanding of the static and fatigue material behaviour is crucial. Up till now, it is unsure whether SCC performs better, worse, or equally under fatigue loading conditions. Therefore, in this study, destructive four-point bending tests are performed on large beams, made from VC and SCC, both statically and cyclically (at different loading rates). A comparison of the deflection, strain, crack pattern and crack width evolution of the different concrete types is made. The results reveal some significant differences regarding concrete strain and crack width development during the cyclic tests.

The Effect of Polypropylene Fiber on the Mechanical Properties of Self-Compacting Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1325-1329
Author(s):  
Ye Ran Zhu ◽  
Jun Cai ◽  
Dong Wang ◽  
Guo Hong Huang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Polypropylene Fiber ◽  
Flexural Properties ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Bending Tests ◽  
Flexural Toughness ◽  
Four Point Bending

This paper investigates the mechanical properties (compressive strength, splitting tensile strength and flexural toughness) of polypropylene fiber reinforced self-compacting concrete (PFRSCC). The effect of the incorporation of polypropylene fiber on the mechanical properties of PFRSCC is determined. Four point bending tests on beam specimens were performed to evaluate the flexural properties of PFRSCC. Test results indicate that flexural toughness and ductility are remarkably improved by the addition of polypropylene fiber.

scholarly journals Fatigue Behaviour of Thin Coated Al 7075 Alloy with Low Temperature PVD Coatings

2013 ◽  
Vol 577-578 ◽  
pp. 221-224 ◽  
Author(s):  
Sergio Baragetti ◽  
Riccardo Gerosa ◽  
Francesco Villa
Keyword(s):  
Aluminium Alloys ◽  
Deposition Temperature ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Pvd Coatings ◽  
Bending Tests ◽  
Al 7075 ◽  
Rotating Bending ◽  
Step Loading ◽  
7075 Alloy

7075-T6 is one of the most performing aluminium alloys, considering its mechanical properties and good fatigue behaviour. In this work the influence of WC/C and DLC PVD coatings on the fatigue behaviour was investigated by rotating bending tests at 2·105cycles. The fatigue behaviour of polished and untreated specimens was considered as reference. In order to decouple the effect of the deposition temperature from the coating one, some uncoated specimens were submitted to the thermal cycles of the WC/C and DLC processes and then tested under fatigue loading. Fatigue life was determined using a step-loading technique. SEM micrographs of the fracture surfaces were taken in order to characterize the fatigue mechanisms of coated and uncoated specimens.

Fatigue Loading Tests and Acceptance Criteria of Reinforced Pre-Stressed Concrete Railway Sleepers

2015 ◽  
Vol 727-728 ◽  
pp. 583-586
Author(s):  
Marcela Karmazínová
Keyword(s):  
Crack Width ◽  
Fatigue Loading ◽  
Fatigue Behaviour ◽  
Test Results ◽  
Acceptance Criteria ◽  
Loading Tests ◽  
The Moment ◽  
Total Fracture

The paper is focused on the problems of the fatigue behaviour, failure and resistance of reinforced pre-stressed concrete railway sleepers, developed and verified continuously in the period of several last years. The results of fatigue loading tests are presented for the sleepers for both wide and narrow track gauge. Test results have been evaluated using the criteria for the acceptance based on the load corresponding to the prescribed crack width and the load at the moment of total fracture.

scholarly journals Theoretical and Experimental Fatigue Strength Calculations of Lips Compensating Circumferential Backlash in Gear Pumps

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 251
Author(s):  
Piotr Osiński ◽  
Grzegorz Chruścielski ◽  
Leszek Korusiewicz
Keyword(s):  
Maximum Stress ◽  
Theoretical Calculations ◽  
Fatigue Loading ◽  
Minimum Thickness ◽  
Bending Tests ◽  
External Gear Pumps ◽  
Gear Pumps ◽  
In Series ◽  
Number Of Cycles ◽  
Technical Solutions

This article presents theoretical and experimental calculations of the minimum thickness of a compensation lip used in external gear pumps. Pumps of this type are innovative technical solutions in which circumferential backlash (clearance) compensation is used to improve their volumetric and overall efficiency. However, constructing a prototype of such a pump requires long-lasting research, and the compensation lip is its key object, due to the fact that it is an element influenced by a notch and that it operates in unfavorable conditions of strong fatigue stresses. The theoretical calculations presented in this article are based on identifying maximum stress values in a fatigue cycle and on implementing the stress failure condition and the conditions related to the required value of the fatigue safety factor. The experimental research focuses on static bending tests of the lips as well as on the fatigue loading of the lips in series of tests at increasing stress values until lip failure due to fatigue. The tests allowed the minimum lip thickness to be found for the assumed number of fatigue cycles, which is 2.5 times the number of cycles used in wear margin tests.

Investigation of Grouted Coupler Connection Details for Accelerated Bridge Construction

2021 ◽  
pp. 036119812199939
Author(s):  
Brent Phares ◽  
Yoon-Si Lee ◽  
Travis K. Hosteng ◽  
Jim Nelson
Keyword(s):  
Crack Width ◽  
High Performance ◽  
Static Load ◽  
High Performance Concrete ◽  
Precast Concrete ◽  
Chloride Penetration ◽  
Load Testing ◽  
Test And Evaluation ◽  
Load Tests ◽  
Precast Elements

This paper presents a laboratory investigation on the performance of grouted rebar couplers with the connection details similar to those utilized on the precast concrete elements of the Keg Creek Bridge on US 6 in Iowa. The testing program consisted of a series of static load tests, a fatigue test, and evaluation of the chloride penetration resistance of laboratory specimens. The goal of this testing was to evaluate the ability of the grouted rebar couplers to develop flexural capacity at the joint between the precast elements as well as the durability of the connection. For structural load testing, seven full-scale specimens, each with #14 epoxy-coated rebars spliced by epoxy-coated grouted couplers, were fabricated and tested in three different loading cases: four-point bending, axial tension plus bending, and a cyclic test of the system in bending. The static load testing demonstrated that the applied axial load had a minimal effect on the formation of cracks and overall performance of the connection. When ultra-high performance concrete was used as a bedding grout, the initiation of crack was slightly delayed but no considerable improvement was observed in the magnitude of the crack width during loading or the crack closure on unloading. The results of the seventh specimen, tested in fatigue to 1 million cycles, showed little global displacement and crack width throughout the test, neither of which expanded measurably. No evidence of moisture or chloride penetration was detected at the grouted joint during the 6-month monitoring.

Comparison of results obtained by static 3- and 4-point bending and flexural vibration tests on solid wood, MDF, and 5-plywood

Holzforschung ◽  
2013 ◽  
Vol 67 (8) ◽  
pp. 941-948 ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Medium Density Fiberboard ◽  
Flexural Vibration ◽  
Solid Wood ◽  
Bending Tests ◽  
Four Point Bending ◽  
Flexural Vibration Test ◽  
The Difference ◽  
Vibration Tests

Abstract The flexural Young’s modulus of western hemlock, medium-density fiberboard, and 5-plywood (made of lauan) has been determined by conducting three- and four-point bending tests with various span lengths and by flexural vibration test. The Young’s modulus was significantly influenced by the deflection measurement method. In particular, the Young’s modulus was not reliable based on the difference between the deflections at two specific points in the specimen, although this test is standardized according to ISO 3349-1975 and JIS Z2101-2009.

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