Durability of Modified Expanded Polystyrene Concrete after Dynamic Cyclic Loading

EPS concrete was produced by mixing the expanded polystyrene spheres (EPS) and polymer emulsion and thickener to the matrix concrete, and this concrete had good vibration energy absorption characteristics. Based on the experimental data obtained on EPS volume ratio of 0%, 20%, 30%, and 40% by replacing matrix or coarse aggregate, the two design styles had nearly the same compressive strength. By applying frequency of 5 Hz, 50000 or 100000 times, 40 KN, 50 KN, and 60 KN cyclic loading, it is shown that the higher the inclusion size was, the lower the compressive strength of the EPS concrete would be; the larger the applying dynamic cyclic load was, the more obvious the compressive strength changing would be. Meanwhile, the strength of EPS concrete had no evident change after durability test. The results of this research had practical significance on using EPS concrete in some long-term cyclic dynamic load engineering.

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Study on the Fatigue and Durability Behavior of Structural Expanded Polystyrene Concretes

Materials ◽

10.3390/ma12182882 ◽

2019 ◽

Vol 12 (18) ◽

pp. 2882 ◽

Cited By ~ 1

Author(s):

Quan You ◽

Linchang Miao ◽

Chao Li ◽

Huanglei Fang ◽

Xiaodong Liang

Keyword(s):

Cyclic Loading ◽

Cyclic Load ◽

Dynamic Performance ◽

Plain Concrete ◽

Expanded Polystyrene ◽

Structural Elements ◽

Sulfate Resistance ◽

Erosion Test ◽

Test Process

The fatigue and durability characteristics of structural expanded polystyrene concrete (EPS) are especially important when it was applied for structural elements in long-term service. In order to study the fatigue and durability behavior of structural EPS concrete, the long-term cyclic loading experiments and wetting–drying (W-D) cyclic experiments were conducted, respectively. The structural EPS concrete was found to have a relatively large damping and a fairly low dynamic elastic modulus under long-term cyclic load, which illustrated that it had a better energy absorption effect and toughness than plain concrete of the same strength level. Even if fine cracks appeared during the cyclic loading process, the relevant dynamic performance remained stable, which indicated that the structural EPS concrete had superior fatigue stability. In W-D cyclic experiments, the structural EPS concrete exhibited superior sulfate resistance. During the erosion test process, there was a positive correlation between the mass change and the evolution of the compressive strength of the structural EPS concrete, which indicated that ΔmB could be substituted for Δf to evaluate the degree of the structural EPS concrete eroded by sulfate attack. The study focuses on the fatigue performance and sulfate resistance of structural EPS concrete and is of important engineering value for promoting practical long-term operations.

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Deterioration of Coal Microstructure under Discontinuous Cyclic Loading Based on Nuclear Magnetic Resonance

Applied Sciences ◽

10.3390/app11010462 ◽

2021 ◽

Vol 11 (1) ◽

pp. 462

Author(s):

Zhe Xiang ◽

Nong Zhang ◽

Zhengzheng Xie ◽

Chenghao Zhang

Keyword(s):

Nuclear Magnetic Resonance ◽

Compressive Strength ◽

Magnetic Resonance ◽

Cyclic Loading ◽

Uniaxial Compressive Strength ◽

Coal Sample ◽

Cyclic Load ◽

Coal Pillar ◽

Holding Time

To study the damage and destruction behavior of small coal pillars in coal mine roadway driving along gobs under long-term in-situ stress and multiple engineering disturbances, an unconfined compression experiment under a discontinuous cyclic load was designed, with the holding time as a variable. An electro-hydraulic servo rock testing machine was used to impose a discontinuous cyclic load on the coal sample and perform a final uniaxial compressive strength test. The changes in pore number and diameter in the coal under stress were monitored by nuclear magnetic resonance analysis. An increase in holding time in the discontinuous cyclic loading resulted in a significant increase in the number and diameter of pores in the coal sample; the coal porosity continued to increase, and the proportion of pores in the coal changed. The proportion of micropores decreased gradually, whereas the proportion of mesopores and macropores (cracks) increased. The degree of internal specimen damage increased with an increase of holding time, which resulted in a gradual decrease in final uniaxial compressive strength. Therefore, under the action of a long-term stress, to improve the bearing capacity of the coal pillar while avoiding gas and water influx into the working face in the goaf, the coal pillar should be reinforced with multi-layer and multi-grain grouting.

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Effect of matrix particle size on EPS lightweight concrete properties

MATEC Web of Conferences ◽

10.1051/matecconf/201825101027 ◽

2018 ◽

Vol 251 ◽

pp. 01027

Author(s):

Duc Hoang Minh ◽

Ly Le Phuong

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Lightweight Concrete ◽

Aggregate Size ◽

Expanded Polystyrene ◽

Coarse Aggregates ◽

Concrete Mixtures ◽

Maximum Particle Size ◽

The Matrix ◽

Maximum Particle

Expanded polystyrene lightweight concrete is a composite which can be made by adding expanded polystyrene aggregate in normalweight concrete (as matrix). The research was focused on the effect of properties and volume of the matrix on the properties of lightweight concrete. The results show that properties of structural polystyrene concrete, such as workability and compressive strength, depend on the aggregate size of the matrix. It also shows that decreasing aggregate size of the matrix is the effective way to increase workability and compressive strength of lightweight concrete. When the density of concretes decrease by 200 kg/m³, slump values decrease by about 20 to 30 mm with lightweight concrete mixtures using maximum particle size of 0.63 mm, while slump values decrease by about 40 mm with the mixtures using maximum particle size of 20 mm. At the same density, the compressive strength of the structural polystyrenre concrete significantly decreased when the coarse aggregate diameter greater than 10 mm. Therefore, coarse aggregates with diameter size are smaller than 10 mm was recommended to use for matrix. In the result, expanded polystyrene concrete with density from 1,400 kg/m³ to 2,000 kg/m³ and compressive strength more than 20 MPa for structural application was made.

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Microstructural Observation of Ni-WC Surface Alloyed Carbon Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.335-336.58 ◽

2011 ◽

Vol 335-336 ◽

pp. 58-62

Author(s):

Chang Qing Guo ◽

Qi Huan Wang

Keyword(s):

Transitional Zone ◽

Optical Microscope ◽

Carbide Precipitation ◽

Carbon Steels ◽

Expanded Polystyrene ◽

Polystyrene Spheres ◽

Transitional Layer ◽

The Matrix ◽

Fine Pearlite ◽

Carbide Particles

EPS (expanded polystyrene spheres) templates with thickness of a 10 mm coating on a surface that is mainly consisted of Ni-WC particles, are prepared. Carbon steels containing 0.45C%wt are then cast in the templates using V-EPC process (vacuum expandable pattern casting), forming the surface alloyed steels. The microstructures are observed and analyzed using optical microscope, SEM and EDS. Macrostructural observation showed that the surface alloyed zone is dense and there is no obvious defects, such as gas bubbles, occluded gas holes and delimitation. Microstructural investigations indicate that the samples from top to bottom are obviously consisted of three different zones, i.e., the top alloyed zone, the interim transitional zone and the bottom matrix zone. Ni-WC particles are totally decomposed during the molten steel infiltration. The microstructures in the surface alloyed zone are consisted of small amounts of fine WC+W2C carbides, large amounts of M3C+M7C3 carbides and dendritic matrix. There is a fine pearlite strip at the top of the transitional layer. Small amounts of carbide particles within the matrix grains and net carbide precipitation in the grain boundaries at the transitional zone can be observed.

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Mathematical Simulation of Bottom Ash Effect and Expanded Polystyrene on the Polystyrene Concrete Properties

Materials Science Forum ◽

10.4028/www.scientific.net/msf.974.312 ◽

2019 ◽

Vol 974 ◽

pp. 312-318

Author(s):

Lam Tang Van ◽

Dien Vu Kim ◽

Boris I. Bulgakov ◽

Sofia I. Bazhenova

Keyword(s):

Mathematical Model ◽

Compressive Strength ◽

Bottom Ash ◽

Green Light ◽

Expanded Polystyrene ◽

Second Order ◽

Dry Density ◽

Regression Equations ◽

Polystyrene Spheres ◽

Concrete Properties

Nowadays various light concrete types have many advantages as compared to heavyweight concrete (total structures mass decrease, increased thermophysical properties, less material consumption). Various industrial wastes use such as fly ashes, slag and bottom ash was suggested to enhance the light concretes effectiveness. This is greatly important for a green light concrete production since it is very important to obtain new types of environmentally friendly materials using wastes. The article substantiates the light concrete use and creation with organo-mineral additives based on industrial waste, analysis of the second-order mathematical model describing the bottom ash (BA) amount effect of Vung Ang TPP and expandable polystyrene spheres (EPS) on the light concrete density and compressive strength at the age of 28 days of normal hardening is done. In this work, the BA and EPS amounts varied from 14.5 to 45.5%, respectively, of the cement weight and from 24.5 to 55.5% of the concrete mix volume. The effect of expanded polystyrene spheres (EPS) and bottom ash (BA) TPP "Vung Ang" amounts as the input parameters on the polystyrene concrete properties (PCP) were investigated in this study. On the one hand, various proportions of BA (14.5, 20, 30, 40 and 45.5%) were blended in concrete mixes as partial weight replacement for Portland cement. On the other hand, EPS amount was replaced by the fresh concrete volume in the range from 24.5% to 55.5%. Additionally, the central composite design method of Box-Wilson for second order factors was used to predict the EPS and BA effects on the polystyrene concrete properties. The results showed that the proposed regression equations of this mathematical model achieved an adequate prediction accuracy. Hence, the effects of both bottom ash contents and expanded polystyrene spheres on the dry density and 28-day compressive strength of the PSC-specimens were significant. In the future, further investigations have to be carried out to study the quality prediction of green light concrete containing various wastes.

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Research on the Economic Vitality of the Northeast China

Journal of Economic Science Research ◽

10.30564/jesr.v3i3.1829 ◽

2020 ◽

Vol 3 (3) ◽

Author(s):

Jiayue Jiao

Keyword(s):

Northeast China ◽

Practical Significance ◽

Economic Policies ◽

Regional Competitiveness ◽

Regional Economic ◽

Important Indicator ◽

Depth Study ◽

Long Term Impact ◽

Economic Vitality

Economic vitality is an important indicator of regional competitiveness. The demand for talents and the vitality of enterprises in different regions are obvious to all and have practical significance. Therefore, it is necessary to establish a survey data model and conduct in-depth study on improving regional economic vitality from the perspective of policy.Based on a variety of forecasting methods, this paper analyzes the short-term and long-term impact of economic policies in Northeast China, and finally puts forward the factors that affect the economic vitality of northeast policies. Finally, the paper puts forward the feasibility and targeted suggestions of strengthening regional economic vitality, obtaining long-term development and building a more competitive city in the new era.

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KUBOTA KNC-03

Alloy Digest ◽

10.31399/asm.ad.ni0676 ◽

2010 ◽

Vol 59 (1) ◽

Keyword(s):

Compressive Strength ◽

High Temperature ◽

Physical Properties ◽

Tensile Properties ◽

High Strength ◽

Temperature Performance ◽

Resistance To Oxidation

Abstract Kubota KNC-03 is a grade with a combination of high strength and excellent resistance to oxidation. These properties make this alloy suitable for long-term service at temperature up to 1250 deg C (2282 deg F). This datasheet provides information on physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: Ni-676. Producer or source: Kubota Metal Corporation, Fahramet Division. See also Alloy Digest Ni-662, April 2008.

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Review of the Durability of Polymer Electrolyte Membrane Fuel Cell in Long-Term Operation: Main Influencing Parameters and Testing Protocols

Energies ◽

10.3390/en14134048 ◽

2021 ◽

Vol 14 (13) ◽

pp. 4048

Author(s):

Huu Linh Nguyen ◽

Jeasu Han ◽

Xuan Linh Nguyen ◽

Sangseok Yu ◽

Young-Mo Goo ◽

...

Keyword(s):

Fuel Cell ◽

Polymer Electrolyte ◽

Failure Modes ◽

Polymer Electrolyte Membrane ◽

Durability Test ◽

Term Operation ◽

Electrolyte Membrane ◽

Transportation Applications ◽

Testing Protocols

Durability is the most pressing issue preventing the efficient commercialization of polymer electrolyte membrane fuel cell (PEMFC) stationary and transportation applications. A big barrier to overcoming the durability limitations is gaining a better understanding of failure modes for user profiles. In addition, durability test protocols for determining the lifetime of PEMFCs are important factors in the development of the technology. These methods are designed to gather enough data about the cell/stack to understand its efficiency and durability without causing it to fail. They also provide some indication of the cell/stack’s age in terms of changes in performance over time. Based on a study of the literature, the fundamental factors influencing PEMFC long-term durability and the durability test protocols for both PEMFC stationary and transportation applications were discussed and outlined in depth in this review. This brief analysis should provide engineers and researchers with a fast overview as well as a useful toolbox for investigating PEMFC durability issues.

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Effect of Waste Glass on the Properties and Microstructure of Magnesium Potassium Phosphate Cement

Materials ◽

10.3390/ma14082073 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2073

Author(s):

Qiubai Deng ◽

Zhenyu Lai ◽

Rui Xiao ◽

Jie Wu ◽

Mengliang Liu ◽

...

Keyword(s):

Compressive Strength ◽

Glass Powder ◽

Setting Time ◽

Potassium Phosphate ◽

Heat Of Hydration ◽

Waste Glass ◽

Hydration Heat ◽

Magnesium Potassium Phosphate Cement ◽

The Matrix ◽

Powder Content

Waste glass is a bulk solid waste, and its utilization is of great consequence for environmental protection; the application of waste glass to magnesium phosphate cement can also play a prominent role in its recycling. The purpose of this study is to evaluate the effect of glass powder (GP) on the mechanical and working properties of magnesium potassium phosphate cement (MKPC). Moreover, a 40mm × 40mm × 40mm mold was used in this experiment, the workability, setting time, strength, hydration heat release, porosity, and microstructure of the specimens were evaluated. The results indicated that the addition of glass powder prolonged the setting time of MKPC, reduced the workability of the matrix, and effectively lowered the hydration heat of the MKPC. Compared to an M/P ratio (MgO/KH2PO4 mass ratio) of 1:1, the workability of the MKPC with M/P ratios of 2:1 and 3:1 was reduced by 1% and 2.1%, respectively, and the peak hydration temperatures were reduced by 0.5% and 14.6%, respectively. The compressive strength of MKPC increased with an increase in the glass powder content at the M/P ratio of 1:1, and the addition of glass powder reduced the porosity of the matrix, effectively increased the yield of struvite-K, and affected the morphology of the hydration products. With an increase in the M/P ratio, the struvite-K content decreased, many tiny pores were more prevalent on the surface of the matrix, and the bonding integrity between the MKPC was weakened, thereby reducing the compressive strength of the matrix. At less than 40 wt.% glass powder content, the performance of MKPC improved at an M/P ratio of 1:1. In general, the addition of glass powders improved the mechanical properties of MKPC and reduced the heat of hydration.

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