Correlation Research of Concrete Mix Proportion on Cement Dosage in Coarse Aggregate

2014 ◽  
Vol 556-562 ◽  
pp. 692-695
Author(s):  
Zhang Bo
Keyword(s):  
Cost Reduction ◽  
High Speed ◽  
Coarse Aggregate ◽  
Social Economy ◽  
Project Design ◽  
Mixing Ratio ◽  
Project Cost ◽  
Mix Proportion ◽  
Concrete Mix ◽  
Selection Of

Along with the high-speed development of social economy in our country, the country invests more in infrastructure construction. The ratio of concrete in coarse aggregate has great impact on engineering quality. If there are any proportion problems, a certain degree of engineering accidents and sometimes even devastating accidents can be caused. This article studies the correlation between concrete proportioning and cement dosage in coarse aggregate through practices, discovers the importance of reasonable selection of coarse aggregate in economic cement mixing ratio configuration process, and realizes the implementation of project cost reduction in project design.

scholarly journals Functional Method of Designing Self-Compacting Concrete

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 267
Author(s):  
Tomasz Rudnicki
Keyword(s):  
Coarse Aggregate ◽  
Cement Mortar ◽  
Experimental Studies ◽  
Functional Method ◽  
Structural Viscosity ◽  
Self Compacting Concrete ◽  
Theoretical Assumptions ◽  
Concrete Mix ◽  
Selection Of ◽  
Double Coating

The article presents a new functional method of designing self-compacting concrete (SCC). The assumptions of the functional method of designing self-compacting concrete were based on the double coating assumption (i.e., it was assumed that the grains of coarse aggregate were coated with a layer of cement mortar, whereas the grains of sand with cement paste). The proposed method is composed of four stages, each of which is responsible for the selection of a different component of the concrete mix. The proposed designing procedure takes into consideration such a selection of the mineral skeleton in terms of the volumetric saturation of the mineral skeleton, which prevents the blocking of aggregate grains, and the designed liquid phase demonstrated high structural viscosity and low yield stress. The performed experimental studies, the simulation of the elaborated mathematical model fully allowed for the verification of the theoretical assumptions that are the basis for the development of the method of designing self-compacting concrete.

Selection of the Optimal Type of Bored-Injection Piles Strengthening of Weak Bases of High-Speed Railway Lines

2019 ◽  
pp. 40-44
Author(s):  
N.S. SOKOLOV ◽  
◽  
S.S. VIKTOROVA ◽  
I.P. FEDOSEEVA ◽  
G.M. SMIRNOVA ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Railway ◽  
Weak Bases ◽  
Selection Of ◽  
Optimal Type

scholarly journals Energy Absorption Characteristics of PVC Coarse Aggregate Concrete under Impact Load

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Shi Hu ◽  
Huaming Tang ◽  
Shenyao Han
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
High Speed ◽  
Coarse Aggregate ◽  
Specific Energy Absorption ◽  
Low Speed ◽  
High Speed Impact ◽  
Aggregate Content ◽  
Dynamic Compressive Strength ◽  
Absorption Characteristics

AbstractIn this paper, polyvinyl chloride (PVC) coarse aggregate with different mixing contents is used to solve the problems of plastic pollution, low energy absorption capacity and poor damage integrity, which provides an important reference for PVC plastic concrete used in the initial support structures of highway tunnels and coal mine roadway. At the same time, the energy absorption characteristics and their relationship under different impact loads are studied, which provides an important reference for predicting the energy absorption characteristics of concrete under other PVC aggregate content or higher impact speed. This study replaced natural coarse aggregate in concrete with different contents and equal volume of well-graded flaky PVC particles obtained by crushing PVC soft board. Also, slump, compression, and splitting strength tests, a free falling low-speed impact test of steel balls and a high-speed impact compression test of split Hopkinson pressure bar (SHPB) were carried out. Results demonstrate that the static and dynamic compressive strength decreases substantially, and the elastic modulus and slump decrease slowly with the increase of the mixing amount of PVC aggregate (0–30%). However, the energy absorption rate under low-speed impact and the specific energy absorption per MPa under high-speed impact increase obviously, indicating that the energy absorption capacity is significantly enhanced. Regardless of the mixing amount of PVC aggregate, greater strain rate can significantly enhance the dynamic compressive strength and the specific energy absorption per MPa. After the uniaxial compression test or the SHPB impact test, the relative integrity of the specimen is positively correlated with the mixing amount of PVC aggregate. In addition, the specimens are seriously damaged with the increase of the impact strain rate. When the PVC aggregate content is 20%, the compressive strength and splitting strength of concrete are 33.8 MPa and 3.26 MPa, respectively, the slump is 165 mm, the energy absorption rate under low-speed impact is 89.5%, the dynamic compressive strength under 0.65 Mpa impact air pressure is 58.77 mpa, and the specific energy absorption value per MPa is 13.33, which meets the requirements of shotcrete used in tunnel, roadway support and other impact loads. There is a linear relationship between the energy absorption characteristics under low-speed impact and high-speed impact. The greater the impact pressure, the larger the slope of the fitting straight line. The slope and intercept of the fitting line also show a good linear relationship with the increase of impact pressure. The conclusions can be used to predict the energy absorption characteristics under different PVC aggregate content or higher-speed impact pressure, which can provide important reference for safer, more economical, and environmental protection engineering structure design.

Experimental Research on Peridotite Concrete for Neutron Shielding

2013 ◽  
Vol 423-426 ◽  
pp. 1031-1035
Author(s):  
Jin Jun Wang ◽  
Guo Feng Li ◽  
De Chuan Meng
Keyword(s):  
Neutron Shielding ◽  
Crystal Water ◽  
Concrete Aggregates ◽  
Mix Proportion ◽  
Concrete Mix ◽  
Energy Neutron ◽  
Transmission Data ◽  
Shielding Material ◽  
Different Thickness ◽  
Thermal Stability Of

Peridotite containing high crystal water is used as concrete aggregates in this research. The mineral composition and thermal stability of peridotite are experimentally analyzed, and the concrete mix proportion design is optimized. The neutron shielding performance of peridotite concrete specimens are tested using 241Am-Be neutron source. The transmission data of different thickness and different energy neutron are calculated. It concludes that peridotite concrete has a good performance in neutron shielding and peridotite is an excellent neutron shielding material.

Current Design Activities on British Railways

1969 ◽  
Vol 184 (4) ◽  
pp. 5-14
Author(s):  
J. F. Thring
Keyword(s):  
High Speed ◽  
Design Review ◽  
New Developments ◽  
Maintenance Costs ◽  
Current Design ◽  
Design Activities ◽  
Selection Of ◽  
Freight Vehicles

With the identification of profitable freight areas and the selection of growth traffics for development has come the need to review in detail the running gear and, in particular, the suspensions of both 4-wheeled and bogie vehicles. This design review has been aimed at ensuring a high-speed capability for all new freight vehicles coupled with safety at all times, low maintenance costs, and maximum availability. After reviewing traditional suspensions, in wide use, with reference to their known strengths and weaknesses, the paper discusses in some detail the philosophy now being applied in B.R. design offices to new freight running gear, for both 4-wheeled and bogie vehicles, to ensure satisfactory achievement of technical objectives. Examples of new developments are provided, together with comments on progress to date.

Comparative Evaluation of MoS2 and WS2 as Powder Lubricants in High Speed, Multi-Pad Journal Bearings

1999 ◽  
Vol 121 (3) ◽  
pp. 625-630 ◽  
Author(s):  
C. Fred Higgs ◽  
Crystal A. Heshmat ◽  
Hooshang Heshmat
Keyword(s):  
Comparative Evaluation ◽  
High Speed ◽  
Solid Lubricants ◽  
Extreme Environment ◽  
Journal Bearings ◽  
Lubricating Film ◽  
Constant Friction ◽  
Traction Coefficient ◽  
Limiting Value ◽  
Selection Of

As part of a program to develop solid/powder-lubricated journal bearings, a comparative evaluation has been performed to aid in determining whether MoS2 and WS2 powder are suitable lubricants for high-speed, extreme-environment multi-pad journal bearings. Plots of traction coefficients, friction, frictional power loss, and bearing pad temperature are presented as a means for comparing various powder lubricants. This paper primarily focuses on experiments carried out on a three-pad journal bearing and a disk-on-disk tribometer. Results showed that MoS2 traction curves resemble that of SAE 10 synthetic oil. Unlike liquid lubricants, powder films have a limiting shear strength property. Once the powder reaches this limiting value, the maximum traction coefficient is limited and the powder essentially shears along sliding walls. Experimental traction data shows evidence of this property in various powders. The thermal performance of the bearing was evaluated at speeds up to 30,000 rpm and loads up to 236 N. Although WS2 displayed constant friction coefficient and low temperature with increasing dimensionless load, MoS2 exhibited frictional behavior resembling that of a hydrodynamic lubricating film. In this paper, an attempt has been made to provide a criterion for the selection of solid lubricants for use in those tribosystems that may be operated in a high speed/load regime (i.e., high strain rates) as an alternative yard stick to conventional comparative approaches.

Selection of Rotor Retaining Sleeve Considering Loss Density and Prototype Machine Operating Characteristics in 2-pole Ultra-High-Speed Motors

2021 ◽  
Vol 141 (6) ◽  
pp. 472-485
Author(s):  
Takayuki Iida ◽  
Masatsugu Takemoto ◽  
Satoshi Ogasawara ◽  
Koji Orikawa ◽  
Ikuya Sato ◽  
...  
Keyword(s):  
High Speed ◽  
Operating Characteristics ◽  
Ultra High Speed ◽  
Selection Of

Investigating Different Metrics for Evaluation and Selection of Mutation Operators for Java

2021 ◽  
Vol 31 (03) ◽  
pp. 311-336
Author(s):  
Shweta Rani ◽  
Bharti Suri
Keyword(s):  
Cost Reduction ◽  
Test Suite ◽  
Cost Benefits ◽  
Powerful Technique ◽  
Reduction Techniques ◽  
Mutation Operators ◽  
Different Types ◽  
Java Programs ◽  
Selective Mutation ◽  
Selection Of

Mutation testing is a successful and powerful technique, specifically designed for injecting the artificial faults. Although it is effective at revealing the faults, test suite assessment and its reduction, however, suffer from the expense of executing a large number of mutants. The researchers have proposed different types of cost reduction techniques in the literature. These techniques highly depend on the inspection of mutation operators. Several metrics have been evolved for the same. The selective mutation technique is most frequently used by the researchers. In this paper, the authors investigate different metrics for evaluating the traditional mutation operators for Java. Results on 13 Java programs indicate how grouping few operators can impact the effectiveness of an adequate and minimal test suite, and how this could provide several cost benefits.

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