Application of Fibres in Xiluodu Hydropower Station and Assessment on its Cracking Resistance

2014 ◽  
Vol 1065-1069 ◽  
pp. 1743-1747
Author(s):  
Xia Chen ◽  
Hua Quan Yang ◽  
Jian Feng Zhang
Keyword(s):  
Elastic Modulus ◽  
Stress Test ◽  
Hydropower Station ◽  
Test Machine ◽  
Cracking Resistance ◽  
Plate Method ◽  
Obvious Effect ◽  
Good Shape ◽  
Mechanical Performances ◽  
Cracking Sensitivity

Investigation was launched on cracking resistance of concrete with incorporation of different fibres in terms of mechanical performances, shrinkage and cracking sensitivity with employment of plate and temperature and stress test machine. Results indicated that little difference was observed on strength, Young’s elastic modulus and autogenous volume deformity among concrete made from different fibres, and incorporation of PVA fibres elevated the ultimate tension by 8 per cent in comparison with the referenced concrete while PP fiber showed no obvious effect. Cracking resistance of concrete was improved from Grade V to Grade I with incorporation of PVA and PP fibres through plate method and concrete made with PVA was rated better in cracking resistance because of lower cracking temperature according to RILEM TC119. Based on investigation launched above, PVA fibre was finally selected and so far the dam was in good shape and runs well.

Influence of Aggregates on Cracking Sensitivity of Concrete

2012 ◽  
Vol 204-208 ◽  
pp. 3299-3302 ◽  
Author(s):  
Xia Chen ◽  
Jian Jun Yan ◽  
Hua Quan Yang
Keyword(s):  
Compressive Strength ◽  
Stress Test ◽  
Interfacial Transition Zone ◽  
Cement Matrix ◽  
Test Machine ◽  
Test Results ◽  
Concrete Cracking ◽  
Natural Aggregate ◽  
Compressive Strength Of Concrete ◽  
Cracking Sensitivity

Concrete cracking sensitivity made from different aggregates was compared with employment of advanced temperature and stress test machine by tracking thermal and stress development of concrete with age and elements distribution in interfacial transition zone of each concrete was explored by SEM and EDS. Test results indicated that compressive strength of concrete made from basalt and limestone was greater than diorite and natural aggregate and crack resistance of concrete based on cracking sensitivity comparison in terms of cracking temperature varying from minus 0.3°C to minus 2.5°C as diorite, basalt, limestone and natural aggregate. Elements Ca and Mg were apparently accumulated in vicinity of ITZ and some reaction between limestone and cement matrix might have taken place which blurred the boundary between aggregates and cement matrix.

Crack Resistance of Concrete with Incorporation of Light-Burnt MgO

2010 ◽  
Vol 168-170 ◽  
pp. 1348-1352
Author(s):  
Xia Chen ◽  
Hua Quan Yang ◽  
Shi Hua Zhou ◽  
Jian Jun Yan
Keyword(s):  
Crack Resistance ◽  
Compressive Stress ◽  
Stress Test ◽  
Cementitious Materials ◽  
Maximum Temperature ◽  
Test Machine ◽  
Cracking Resistance ◽  
Maximum Compressive Stress ◽  
Cracking Tendency ◽  
Cracking Stress

The advanced Temperature and Stress Test Machine was introduced to evaluate the cracking resistance of concrete with inclusion of light-burnt MgO under full restraint by tracking thermal and deformation development. Results showed that light-burnt MgO being incorporated ranging between 4 per cent and 6 per cent by mass of cementitious materials was beneficial to increase the maximum compressive stress and cracking stress of concrete by 0.37MPa and 0.2MPa on average respectively. The maximum temperature was slightly reduced from 59.8°C to 66.2°C while cracking temperature was significantly decreased from 0.8°C to minus 5.6°C. Sensitive anti-cracking coefficient F was forwarded to assess the early cracking tendency of concrete and in general, inclusion of 4 per cent light-burnt MgO with activity of 109s was rated the best in crack resistance.

Study on the Performances and Interfacial Structure of Magnesium Hydroxide Whiskers/ABS Composites

2011 ◽  
Vol 109 ◽  
pp. 46-50
Author(s):  
Yu Zhi Jiang ◽  
Li Li Zhang ◽  
Yan Bo Li
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Magnesium Hydroxide ◽  
Testing Machine ◽  
Surface Modifications ◽  
Interfacial Structure ◽  
Melt Extrusion ◽  
Elongation At Break ◽  
Universal Testing ◽  
Mechanical Performances

The magnesium hydroxide (MH) whiskers / ABS composites were prepared by melt-extrusion with modified whiskers as filler. The mechanical performances, including the tensile strength, elongation at break and elastic modulus, were tested by electronic universal testing machine. The results showed that with the increasing of the whisker dosage, the tensile strength and elongation at break reduced gradually, and the elastic modulus get maximum when it is 25%.The morphology on fracture of composites was analyzed by SEM. The conclusions are the whiskers of surface modifications can be evenly distributed in the composites and bond partly with ABS. that it is necessary to enhance the combine strength of interface on excellence performances of composites.

The Influences of Different Temperature Histories on the Assessment of Cracking Resistance Based on the Concrete Thermal Stress Test

2014 ◽  
Vol 496-500 ◽  
pp. 2426-2430
Author(s):  
Xue Feng Song ◽  
Ying Fei Wang ◽  
Chao Li
Keyword(s):  
Thermal Stress ◽  
Temperature Control ◽  
Stress Test ◽  
Adiabatic Heating ◽  
Control Mode ◽  
Stress Tests ◽  
Cracking Resistance ◽  
Data Matching ◽  
Empirical Tests ◽  
Heating Mode

This paper studied the influences of different temperature histories on the assessment of cracking resistance based on the thermal stress tests, and also initially considered and discussed the effects of several empirical tests on thermal stress tests, including approximate adiabatic heating mode, temperature control mode, archived data matching mode, followed by some proposals regarding the standardizing research of thermal stress test of concrete.

Short Span Compressive Stress-Strain Relation and Model of Molded Pulp Material

2010 ◽  
Vol 450 ◽  
pp. 202-205 ◽  
Author(s):  
Hong Wei Ji ◽  
Huai Wen Wang
Keyword(s):  
Elastic Modulus ◽  
Ultimate Strength ◽  
Loading Rate ◽  
Test Machine ◽  
Stress Strain ◽  
Stress Strain Relation ◽  
Proposed Model ◽  
Two Factors ◽  
Short Span ◽  
Major Factors

Short span compressive experiments of molded pulp specimens were carried out on the SHIMADZU material test machine, resulting in the stress-strain curves. The analytic results indicate that the material density and the loading rate are the two major factors that influence the stress-strain relationships of the molded pulp materials. With the increase of material’s density, elastic modulus and ultimate strength both increase. With the increase of loading rate, elastic modulus decreases whereas ultimate strength increases. By analyzing the test results and the existing models, an improved stress-strain model for molded pulp material, with the two factors taken into consideration, has been proposed. The model coefficients are obtained by fitting against the short span compressive experimental data for the materials with different densities under different loading rate. Comparison made between the experimental results and calculated results indicates that the proposed model can well fit the stress-strain curves of molded pulp.

3D NUMERICAL STUDY OF CELL DEFORMATION AND MIGRATION IN A FLOW CHAMBER

2015 ◽  
Vol 15 (06) ◽  
pp. 1540048
Author(s):  
NA ZHAO ◽  
YUHONG CUI ◽  
XIAOYU WANG ◽  
ZHENZHEN ZHU ◽  
LONG BAI
Keyword(s):  
Elastic Modulus ◽  
Clinical Medicine ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Flow Chamber ◽  
Obvious Effect ◽  
Theoretical Significance ◽  
And Migration ◽  
Numerical Calculation Method

In recent years, the physiological phenomena of cell displacement and deformation in blood vessels have gradually become an important topic in the field of biomechanics, and also have important theoretical significance and application value in clinical medicine. To study the migration and deformation of blood cell, the influence of elastic modulus on its behavior, and the effect of deformation on its migration. A numerical simulation of a single cell displacement and deformation in a flow chamber was conducted in the present study using a computer program based on the fluid–solid coupling. The displacement and deformation of the cells with different elastic modulus as well as the influence of deformation on the movement of the cell were investigated. The results showed that the cell with greater elastic modulus had a smaller deformation in the direction of gravity and fluid velocity. The deformation of the cell had obvious effect on the displacement in the direction of gravity. The smaller the deformation of the cell in the direction of gravity was, the higher the cell could jump. The three-dimensional numerical calculation method adopted in this paper and the results obtained can provide a reference for the study of the cell mechanic behavior in the vessels.

Analysis on Seepage Effects of Plastic Concrete Cut-Off Wall in Construction and Operation Period of Hydropower Station Tail Channel

2014 ◽  
Vol 580-583 ◽  
pp. 1816-1822
Author(s):  
Guo Xin Yan ◽  
Wei Wu
Keyword(s):  
Numerical Calculation ◽  
Unit Length ◽  
Seepage Flow ◽  
Hydropower Station ◽  
Obvious Effect ◽  
Construction Period ◽  
Plastic Concrete ◽  
Operation Period

By numerical calculation, it analyzed the seepage effects of plastic concrete cut-off wall in in construction period. On construction period, the seepage flow from inside of channel to outside at unit length is 0.753m3/h. The seepage flow from under plastic concrete cut-off wall is 0.646m3/h which is 85.79% of total seepage flow. Under certain condition on operation period, the seepage flow from inside of channel to outside at unit length is 0.394m3/h. The seepage flow from under plastic concrete cut-off wall is 0.358m3/h which is 90.86% of total seepage flow. Under another condition on operation period, the seepage flow from inside of channel to outside at unit length is 0.249m3/h. The seepage flow from under plastic concrete cut-off wall is 0.236m3/h which is 94.78% of total seepage flow. In It showed the plastic concrete cut-off wall has obvious effect.

scholarly journals Fused Filament Deposition of PLA: The Role of Interlayer Adhesion in the Mechanical Performances

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 399
Author(s):  
Sara Liparoti ◽  
Daniele Sofia ◽  
Aldo Romano ◽  
Francesco Marra ◽  
Roberto Pantani
Keyword(s):  
Molecular Weight ◽  
Elastic Modulus ◽  
Molecular Diffusion ◽  
Mechanical Performance ◽  
Density Measurement ◽  
Polymer Melt ◽  
Effect Of Temperature ◽  
Plate Temperature ◽  
Crystallinity Degree ◽  
Mechanical Performances

A set of criteria to enhance mechanical performances of standard specimens (Type V, ANSI D368) made of polylactic acid (PLA) were proposed. Fused PLA deposition was conducted with nozzle temperature ranging from 180 to 230 °C and deposition plate temperature ranging from 70 to 110 °C. Optical microscopy, elastic modulus analysis and density measurement allowed emphasizing the effect of temperature field, also measured during the process, on the morphology and the mechanical characteristics of the specimen. Atomic force microscopy revealed a morphology typical of amorphous samples with globular structures. Poor interlayer adhesion was detected in the part of the specimen located at larger distance from the deposition plate, showing an elastic modulus lower than those measured in the central part (220 MPa vs. 500 MPa). The specimen crystallinity degree was below 3%. The molecular weight between entanglements was adopted as a measure of the interlayer molecular diffusion. A successful diffusion and re-entanglement of the polymer melt at the interface was the key to improving mechanical performance. A mathematical model describing the transient heat transfer during the fused PLA deposition and accounting for solidification and the nonisothermal crystallization kinetics was introduced. Simulated temperature evolutions were consistent with the experimental ones. They were related to the mechanical performances, the morphology, and the molecular weight between entanglements of the parts.

scholarly journals Valorization of Recycled Tire Rubber for 3D Printing of ABS- and TPO-Based Composites

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5889
Author(s):  
Fouad Laoutid ◽  
Soumaya Lafqir ◽  
Antoniya Toncheva ◽  
Philippe Dubois
Keyword(s):  
3D Printing ◽  
Automotive Industry ◽  
Fused Deposition Modeling ◽  
Acrylonitrile Butadiene Styrene ◽  
Tire Rubber ◽  
Fused Deposition ◽  
Compression Properties ◽  
Good Shape ◽  
Mechanical Performances ◽  
Manufacturing Technologies

Vulcanized and devulcanized ground tire rubber microparticles have been used as a minor phase in acrylonitrile butadiene styrene copolymer (ABS) and thermoplastic polyolefins (TPO) for the development of materials with desired functionalities by 3D printing. These polymers have been selected because they (i) present part of the plastic waste generated by the automotive industry and (ii) have totally different properties (ABS for its stiffness and robustness and TPO for its softness and ductility). The study aims to improve the circular economy of the automotive industry by proposing a promising route for recycling the generated tire rubber waste. In this respect, emergent technology for plastic processing such as 3D printing is used, as part of the additive manufacturing technologies for the prolongated end of life of recycled plastics originated from automotive waste such as ABS and TPO. The obtained results revealed that (i) the composites are suitable for successful filament production with desired composition and diameter required for successful 3D printing by fused deposition modeling, and that (ii) the optimization of the composition of the blends allows the production of materials with interesting mechanical performances. Indeed, some of the investigated ABS-recycled rubber tire blends exhibit high impact properties as TPO-based composites do, which in addition exhibits elongation at break higher than 500% and good compression properties, accompanied with good shape recovery ratio after compression.

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