Research on Properties of Coastal Natural Spherical Aggregate Concrete

2013 ◽  
Vol 838-841 ◽  
pp. 1810-1813
Author(s):  
Shuang Jian Jiao ◽  
Shuai Wang ◽  
Yong Guo
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Coastal Region ◽  
Fatigue Properties ◽  
Cement Concrete ◽  
Concrete Member ◽  
Spherical Aggregate ◽  
Cement Concrete Pavement ◽  
Engineering Significance ◽  
Stone Concrete

Our country has a long coastline and there are a lot of natural pebbles in coastal region. Applying natural pebbles in concrete is of great engineering significance and prospect. To measure the performance of coastal natural pebbles concrete and study the effect of aggregate on concrete properties, this article put forward a new comparison conditionthe same slump constant and cement dosage based on properties of coastal natural pebbles concrete and crushed stone concrete. Prepare different strength concrete under this condition. The compressive strength of pebble concrete is 100.5%110.7% times of stone concrete. The bending strength and fatigue strength are 97.8%108.1%, 135.8%176.6% respectively. This explains good static and fatigue properties of coastal natural pebbles. Pebble concrete has significant fatigue strength advantages in cement concrete pavement and concrete member under dynamic loading.

Fatigue Bending Strength of Jones Fracture Specific Screw Fixation

2017 ◽  
Vol 39 (4) ◽  
pp. 493-499 ◽  
Author(s):  
James Jastifer ◽  
Kirk A. McCullough
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Fatigue Testing ◽  
Screw Fixation ◽  
Optimal Choice ◽  
Fatigue Properties ◽  
Strength Data ◽  
Screw Design ◽  
Jones Fracture ◽  
Significant Difference

Background: Intramedullary screw fixation is a common method of treating proximal metadiaphyseal fifth metatarsal (ie, Jones) fractures. Fatigue failure is a complication of this fixation. There are many screw designs available, including Jones fracture specific fixation, but the optimal choice of screw design is unknown. The purpose of this study was to compare the fatigue strength of Jones fracture specific screw designs as well as other commonly used screw designs. Our hypothesis was that there would be no difference in fatigue strength for Jones fracture specific screw designs at similar screw diameters. Methods: A study was performed to determine the fatigue bending strength of 5 different screw designs including Jones fracture specific screw designs at 3 different screw diameters. Six screws of each size and design underwent cyclic fatigue testing, and a median fatigue limit (MFL) was determined for each screw design and size. Results: The Stryker Asnis JFX solid 4.0-mm, 5.0-mm, and 6.0-mm screws had a higher MFL than all other screws with similar diameter tested (all P < .0001). Both Jones fracture specific screw designs (Stryker Asnis JFX solid screws and Charlotte Carolina Jones screws) had higher MFLs than the other screw designs tested. Conclusion: This study provides comparative fatigue strength data on larger screw diameters, which have not been previously reported. There was a statistically significant difference in screw fatigue properties at the screw diameters tested. Clinical Relevance: The clinical significance of this study is that it provides surgeons with fatigue strength data to aid in screw selection for Jones fracture fixation.

scholarly journals Statistical Modelling of the Fatigue Bending Strength of Norway Spruce Wood

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 536
Author(s):  
Jernej Klemenc ◽  
Gorazd Fajdiga
Keyword(s):  
Experimental Data ◽  
Fatigue Strength ◽  
Bending Strength ◽  
Mass Density ◽  
Statistical Modelling ◽  
Fatigue Properties ◽  
Novel Approach ◽  
Inverse Power Law ◽  
The Common ◽  
Constant Shape

When wood is used as a structural material, the fact that it is a highly inhomogeneous material, which significantly affects its static and fatigue properties, presents a major challenge to engineers. In this paper, a novel approach to modelling the fatigue-life properties of wood is presented. In the model, the common inverse-power-law relationship between the structural amplitude loads and the corresponding number of load cycles to failure is augmented with the influence of the wood’s mass density, the loading direction and the processing lot. The model is based on the two-parametric conditional Weibull’s probability density function with a constant shape parameter and a scale parameter that is a function of the previously mentioned parameters. The proposed approach was validated using the example of experimental static and fatigue-strength data from spruce beams. It turned out that the newly presented model is capable of adequately replicating the spruce’s S-N curves with a scatter, despite the relatively scarce amount of experimental data, which came from different production lots that were loaded in different directions and had a significant variation in density. Based on the experimental data, the statistical model predicts that the lower density wood has better fatigue strength.

scholarly journals Mechanical Properties Improvement Mechanism of Silica Fume-Modified Ultrafine Cement Used to Repair Pavement Microcracks

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Xiaofei Wang ◽  
Jiangbei Yao ◽  
Xinwei Li ◽  
Yinchuan Guo ◽  
Aiqin Shen ◽  
...  
Keyword(s):  
Silica Fume ◽  
Bonding Strength ◽  
Bending Strength ◽  
Pozzolanic Reaction ◽  
Concrete Pavement ◽  
Interfacial Bonding ◽  
Cement Concrete ◽  
Interfacial Bonding Strength ◽  
Cement Concrete Pavement ◽  
Ultrafine Cement

With heavy modern traffic and natural factors, cement concrete pavement cracks have become increasingly serious. However, most existing inorganic repair materials for cement concrete pavement cracks have low interfacial bonding strength. Ultrafine cement, silica fume (SF), and other admixtures, which are superfine and used to repair fine early cracks, are prepared as the mending material in our research. Compression strength, bending strength, and interfacial bonding strength are studied, and modification mechanisms are discovered by using a powder X-ray diffraction test, thermal analysis, and micromorphology observation. The result shows that mechanical strength of the stable period is improved with the right amount of mixing of SF, which leads to secondary pozzolanic reaction and makes the microstructure of the paste denser. Meanwhile, a large amount of Ca(OH)2 and water in the interface area are consumed by the secondary pozzolanic reaction, which brings out good interfacial effects with no water film between the new paste and existing concrete. Our experiments show that the pastes with 3–5% SF have better bending strength (15%∼17% improvement) and compressive strength (7%∼9% improvement). Interfacial bonding strength is also increased with a certain amount of SF. Tensile shear bonding strength has been improved more than 4 times when SF dosage is more than 3%. Thus, we recommend a paste with 5% SF as the best mixture to be used to repair cracks.

scholarly journals Bending Properties of Additively Manufactured Commercially Pure Titanium (CPTi) Limited Contact Dynamic Compression Plate (LC-DCP) Constructs: Effect of Surface Treatment

2021 ◽  
Author(s):  
Seungjong Lee ◽  
Nabeel Ahmad ◽  
Kayla Corriveau ◽  
Cameron Himel ◽  
Daniel Silva ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Dynamic Compression ◽  
Pure Titanium ◽  
Fatigue Properties ◽  
Single Shot ◽  
Structural Stiffness ◽  
Commercially Pure Titanium ◽  
Bending Tests ◽  
Bending Fatigue

Abstract BackgroundAdditive manufacturing of metallic materials, a layer-wise manufacturing method, is currently gaining attention in the biomedical industry because of its capability to fabricate complex geometries including customized parts fitting to patient requirements. However, one of the major challenges hindering the full implementation of additively manufactured parts in safety-critical applications is their poor mechanical performance under cyclic loading. This study investigated both quasi-static bending properties (bending stiffness, bending structural stiffness, and bending strength) and bending fatigue properties of additively manufactured (AM) commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs. The results were compared with commercially manufactured (CM) counterparts.MethodsAM CPTi LC-DCP with different surface conditions including as-built, single shot-peened, dual shot-peened, and chemically assisted surface enhancement conditions and CM counterparts were mechanically tested based on ASTM International standard for metallic bone plates (ASTM F382). Bending stiffness, bending structural stiffness, and bending strength was measured by quasi-static bending tests, and bending fatigue properties were obtained by cyclic bending tests. ResultsBending stiffness and bending structural stiffness of AM CPTi LC-DCPs are comparable to CM counterparts; however, the bending strength of AM CPTi LC-DCPs is lower than CM counterparts. The fatigue strength of as-built AM CPTi LC-DCPs is lower compared to the CM counterparts. However, after post surface treatments, single shot-peened, dual shot-peened, and chemically assisted surface enhancement AM CPTi LC-DCPs exhibit statistically comparable fatigue strength to the CM CPTi LC-DCPs.ConclusionAM CPTi LC-DCP could be considered as an alternative to CM LC-DCP in applications that require less bending strength (~5.44 N·m). Post surface treatment should be considered on as-built implants to improve fatigue strength.

scholarly journals Research on Application Effect of Mixconverter in Cement Concrete Pavement

2021 ◽  
Vol 261 ◽  
pp. 02075
Author(s):  
Tao Wang ◽  
Tao Liu ◽  
Xiayi Liang ◽  
Hanxin Wei ◽  
Zhigang Zheng ◽  
...  
Keyword(s):  
Bending Strength ◽  
Concrete Strength ◽  
Chloride Ion ◽  
Concrete Pavement ◽  
Hydration Reaction ◽  
Cement Concrete ◽  
Road Pavement ◽  
Cement Concrete Pavement ◽  
Improvement Effect ◽  
Research On Application

In order to improve the strength of cement concrete pavement and reduce pavement cracking, the application effect of the hydration reaction enhancer Mixconverter in cement concrete pavement was studied by testing the compressive strength, bending strength, crack resistance and chloride ion permeability of concrete indoors. The test results show that the addition of Mixconverter to concrete can significantly improve the compressive and flexural strength of concrete, effectively prevent the expansion of plastic shrinkage and cracking of concrete, and significantly reduce the chloride ion diffusion coefficient. Finally, the test road pavement further proves the improvement effect of Mixconverter on concrete strength and cracking.

Stress Analysis of Cement Concrete Pavement under Overweight Loads

2012 ◽  
Vol 446-449 ◽  
pp. 949-953
Author(s):  
Ya Ni Lu ◽  
Tao Li Xiao
Keyword(s):  
Finite Element ◽  
Regression Analysis ◽  
Finite Element Model ◽  
Element Model ◽  
Concrete Pavement ◽  
The Other ◽  
Tension Stress ◽  
Statistical Regression ◽  
Cement Concrete ◽  
Cement Concrete Pavement

Special load has produced serious damage to the concrete pavement because of the great gross weight and heavy axle load, but the present specification has not mentioned this kind of load. On this occasion, Several conditions of critical load are identified through ANSYS finite element model analysis and the formula through statistical regression analysis to the bottom maximum tension stress is drawn up. Which can not only guide the concrete pavement design under the special load but also the result may be referred by the other kinds of engineering.

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