Evaluating the Influence of Mix Proportion Parameters on Anti-Permeability of Green High Performance Concrete with Grey Relational Analysis

2011 ◽  
Vol 250-253 ◽  
pp. 857-860
Author(s):  
Qiao Yan Guan ◽  
Peng Zhang

The aim of this study was to evaluate the influence of mix proportion parameters on anti-permeability of green high performance concrete (GHPC) and find out the main influencing factors. Applying grey relational analysis method, the relational grades between the influencing factors and diffusion coefficient of Cl- of GHPC were calculated. Besides, the sequence result of influencing degree of the factors to affect the anti-permeability was obtained. The result shows that the importance of the factors affecting anti-permeability of GHPC has following sequence: water-binder ratio> sand ratio > dosage of cement> dosage of water reducing admixture > dosage of mineral fillers > dosage of fly ash. In order to improve anti-permeability of GHPC, water-binder ratio and sand ratio must be controlled strictly.

2013 ◽  
Vol 438-439 ◽  
pp. 166-169
Author(s):  
Xin Zhang ◽  
Dong Yang

Applying grey relational analysis method, this paper calculated the relational grades between the mix proportion parameters and the compressive strength, the slump of green high-performance concrete (GHPC) respectively. Besides, the sequence results of influencing degree of the factors affecting the compressive strength and workability were obtained. The results indicate that the compressive strength and slump of GHPC are affected by various mix proportion factors with different sensitivity, and the sensitivity could be well analyzed by the grey relational analysis. Among the four selected parameters of mix proportion such as water to binder ratio, cement dosage, fly ash dosage and sand ratio, the water to binder ratio and the cement dosage greatly influence on the compressive strength of GHPC, the water to binder ratio and the sand ratio greatly influence on the workability of GHPC.


Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3148 ◽  
Author(s):  
Hongyan Chu ◽  
Fengjuan Wang ◽  
Liguo Wang ◽  
Taotao Feng ◽  
Danqian Wang

Ultra-high-performance concrete (UHPC) has received increasing attention in recent years due to its remarkable ductility, durability, and mechanical properties. However, the manufacture of UHPC can cause serious environmental issues. This work addresses the feasibility of using aeolian sand to produce UHPC, and the mix design, environmental impact, and mechanical characterization of UHPC are investigated. We designed the mix proportions of the UHPC according to the modified Andreasen and Andersen particle packing model. We studied the workability, microstructure, porosity, mechanical performance, and environmental impact of UHPC with three different water/binder ratios. The following findings were noted: (1) the compressive strength, flexural strength, and Young’s modulus of the designed UHPC samples were in the ranges of 163.9–207.0 MPa, 18.0–32.2 MPa, and 49.3–58.9 GPa, respectively; (2) the compressive strength, flexural strength, and Young’s modulus of the UHPC increased with a decrease in water/binder ratio and an increase in the steel fibre content; (3) the compressive strength–Young’s modulus correlation of the UHPC could be described by an exponential formula; (4) the environmental impact of UHPC can be improved by decreasing its water/binder ratio. These findings suggest that it is possible to use aeolian sand to manufacture UHPC, and this study promotes the application of aeolian sand for this purpose.


2018 ◽  
Vol 27 (3) ◽  
pp. 180-186 ◽  
Author(s):  
Mohammadkarim Bahadori ◽  
Ehsan Teymourzadeh ◽  
Foad Faizy Bagejan ◽  
Ramin Ravangard ◽  
Mehdi Raadabadi ◽  
...  

Background: One of the techniques used to achieve productivity, employees’ job satisfaction and higher quality goods and services, as well as to solve the problems by using a team, is the formation of quality control circles. Quality control circles enable managers to meet the organization’s and employees’ needs through making effective use of resources and facilities. On the other hand, the quality of services is always affected by uncertainty and ambiguous and implicit judgments, which make its measurement uncertain. Aim: The present study aimed to identify important factors affecting the effectiveness of quality control circles in a hospital, as well as rank them using a combination of fuzzy VIKOR and Grey Relational Analysis (GRA). Methodology: This was an applied, cross-sectional and descriptive–analytical study conducted in 2016. The study population consisted of five academic members and five experts in the field of nursing working in a hospital, who were selected using a purposive sampling method. Also, a sample of 107 nurses was selected through a simple random sampling method using their employee codes and the random-number table. The required data were collected using a researcher-made questionnaire which consisted of 12 factors. The validity of this questionnaire was confirmed through giving the opinions of experts and academic members who participated in the present study, as well as performing confirmatory factor analysis. Its reliability also was verified (α=0.796). The collected data were analyzed using SPSS 22.0 and LISREL 8.8, as well as VIKOR–GRA and IPA methods. Results: The results of ranking the factors affecting the effectiveness of quality control circles showed that the highest and lowest ranks were related to ‘Managers’ and supervisors’ support’ (Š = 6.80, [Formula: see text] = 0.36) and ‘Group leadership’ (Š = 2.63, [Formula: see text] = 0.98). Also, the highest hospital performance was for factors such as ‘Clear goals and objectives’ and ‘Group cohesiveness and homogeneity’, and the lowest for ‘Reward system’ and ‘Feedback system’, respectively. Conclusion: The results showed that although ‘Training the members’, ‘Using the right tools’ and ‘Reward system’ were factors that were of great importance, the organization’s performance for these factors was poor. Therefore, these factors should be paid more attention by the studied hospital managers and should be improved as soon as possible. Applying quality control circles in any organization is very helpful and provides opportunities for maximum use of employees’ creativity, initiative and skills in reaching their and their organization’s goals and objectives, and prepares favorable working conditions for the employees’ optimal performance through increasing the managers’ sense of responsibility and commitment.


Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3385 ◽  
Author(s):  
Min Wang ◽  
Hao Yao

The low flowability and high viscosity of ultra-high performance concrete (UHPC), which is mainly caused by the silica fume (SF) agglomeration and low water–binder ratio, is a severe defect in its engineering applications. Herein, a novel organic–inorganic hybrid (OIH) admixture was synthesized by grafting comb-like polycarboxylate ether (PCE) onto the surface of SF. On the one hand, PCE-grafting could effectively prevent SF agglomeration and improve the dispersion of SF core. The reason being the consumption of polar silicon hydroxyl (Si-OH) groups on the surface of SF and the steric hindrance effect generated from PCE arms. On the other hand, OIH admixture could adsorb onto the surface of cement and SF particles by electrostatic interaction, exhibiting stronger steric hindrance effect than traditional comb-like PCE. As a result, UHPC system with this star-like OIH admixture presented high flowability and low viscosity at low water–binder ratio (0.18).


2013 ◽  
Vol 859 ◽  
pp. 52-55 ◽  
Author(s):  
Yong Qiang Ma

A great deal of experiments have been carried out in this study to reveal the effect of the water-binder ratio and fly ash content on the workability and strengths of GHPC (green high performance concrete). The workability of GHPC was evaluated by slump and slump flow. The strengths include compressive strength and splitting tensile strength. The results indicate that the increase of water-binder ratio can improve the workability of GHPC, however the strengths of GHPC were decreased with the increase of water-binder ratio. When the fly ash content is lower than 40%, the increase in fly ash content has positive effect on workability of GHPC, while the workability begins to decrease after the fly ash content is more than 40%. The addition of fly ash in GHPC has adverse effect on the strengths, and there is a tendency of decrease in the compressive strength and splitting tensile strength of GHPC with the increase of fly ash content.


Sign in / Sign up

Export Citation Format

Share Document