scholarly journals Mechanical Properties and Environmental Evaluation of Ultra-High-Performance Concrete with Aeolian Sand

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.

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.


2014 ◽  
Vol 597 ◽  
pp. 316-319
Author(s):  
Sun Woong Kim ◽  
Wan Shin Park ◽  
Nam Yong Eom ◽  
Yong Il Jang ◽  
Hyun Do Yun ◽  
...  

The supposition that curing at cold weather conditions leads to the loss of compressive strength of the high performance concrete was investigated. This paper addresses the results of an extensive experimental study on the compressive strength under cold weather conditions. The specimen was prepared as it’s inside 100-mm diameter and 200-mm heights cylindrical were used. In this work, high performance concrete was designed a water-binder ratio of 0.40. These tests were carried out to investigate the mechanical properties of HPC for 7 and 28 days. The results properties of HPC with silica fume were effective for compressive strength improvement between 7 to 28 curing days at 5°C, -5°C and-15°C.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4608
Author(s):  
Xianqiang Wang ◽  
Duo Liu ◽  
Yao Zhang ◽  
Yubo Jiao

Acoustic emission (AE) technology is widely used in structural health monitoring. Glass sand (GS) made from waste glass is a promising replacement aggregate for quartz sand (QS) in ultra-high performance concrete (UHPC). This paper addresses the effects of different factors including water-binder ratio, length of basalt fiber (BF) and ratio of GS replacing QS on the fluidity and flexural strength of UHPC notched beam under four-point flexural loads. Meanwhile, the fracture characteristics of UHPC notched beam were characterized through acoustic emission (AE) technique. The results show that water-binder ratio and replacement ratio of GS present a positive correlation with work performance of UHPC, while length of BF exhibits a negative one. The flexural strength of UHPC notched beams can be improved by the decrease of the water-binder ratio and fiber length. The effect of water-binder ratio on flexural strength is the most significant, while the addition of GS presents the minimum one. The fracture characteristics of UHPC notched beams could be favorably characterized by AE parameters. Through the analysis and comparison of the evolution of AE parameters, the differences in fracture properties of UHPC notched beams with different flexural strengths can be realized. Through this study, the fluidity and flexural performance of UHPC produced by replacing QS with GS were demonstrated, which is beneficial to the cleaner production of UHPC. Meanwhile, the AE technique presented great potential for fracture characterization of UHPC notched beam, which also provided a promising method for real-time monitoring of cracking in the diagnosis of UHPC structures.


2014 ◽  
Vol 8 (1) ◽  
pp. 18-21 ◽  
Author(s):  
N. Seshadri Sekhar ◽  
P.N. Raghunath

High performance concrete M60 cubes of 150 mm X 150 mm X 150 mm were tested experimentally under static loading. With the variation in the water binder ratios of 0.25, 0.28, 0.33, 0.39 and hyper plasticizer of 0.6%. 0.8%. 1.0%, 1.2% the cubes were cast and accordingly the cylinders were cast. For each ratio of water binder, 12 cubes and 2 cylinders were cast. Out of 12 cubes, 3 cubes were cured for 7 days, 3cubes for 15 days, 3 cubes for 21 days and the balance 3 cubes for 28 days. All the cubes were tested in a 2000kn compression testing machine. The load deflection curves, stress- strain curves were drawn for each cube and cylinder. The average compressive strength of each mix for different number of days of curing were calculated. The modulus of elasticity was calculated for each design mix.


2013 ◽  
Vol 357-360 ◽  
pp. 588-591 ◽  
Author(s):  
Yan Zhou Peng ◽  
Jin Huang ◽  
Jin Ke

Reactive powder concrete (RPC) is an ultra-high performance concrete (UHPC). Cement and silica fume content of RPC are generally rather high compared to the conventional concrete. The aim of this paper is to decrease the cement content of RPC by using phosphorous slag powder. Firstly the effect of grinding time on the activity index of phosphorous slag was investigated. And then, the mix proportion design of this UHPC containing phosphorous slag powder and silica fume was done through orthogonal design. The results indicate that the utilization of phosphorous slag powder in RPC is feasible when the dosage of phosphorous slag powder is about 35% (by weight of the binder) and the water-binder ratio is less than 0.18. By substituting phosphorous slag powder for a part of cement and keeping the water-binder ratio at about 0.14, UHPC specimens whose content of mineral admixtures, including phosphorous slag powder and silica fume, was about 40%~50% (by weight of the binder) were obtained after they had been cured in 80 °C water for 72 hours. The compressive and flexural strength of those specimens was more than 150 MPa and 20 MPa respectively.


2014 ◽  
Vol 670-671 ◽  
pp. 437-440 ◽  
Author(s):  
Fan Wang ◽  
Shan Suo Zheng ◽  
Xiao Fei Wang

With the improvement of concrete materials and the emergence of new materials, adding silica fume to high-performance concrete (HPC) has been one of the important ways in concrete technology. In this paper, through experimental study on the mechanical performance of HPC with 5%, 10%, 15% and 20% silica fume replacing cement for different water-binder ratio, along with polycarboxylates high performance water-reducing admixture, silica fume has large effects on 28d compressive strength, split tensile strength and flexural strength of the HPC. Meanwhile, due to the different level of water-binder ratio, the relationship between split tensile strength, flexural strength and compressive strength is also obvious linear.


DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez

Ultra-high-performance concrete (UHPC) is a kind of high-tech cementitious material with superb mechanical and durability properties compared to other types of concrete. However, due to the high content of cement and silica fume used, the cost and environmental impact of UHPC is considerably higher than conventional concrete. For this reason, several efforts around the world have been made to develop UHPC with greener and less expensive local pozzolans. This study aimed to design and produce UHPC using local fly ash available in Colombia. A numerical optimization, based on Design of Experiments (DoE) and multi-objective criteria, was performed to obtain a mixture with the proper flow and highest compressive strength, while simultaneously having the minimum content of cement. The results showed that, despite the low quality of local fly ashes in Colombia, compressive strength values of 150 MPa without any heat treatment can be achieved.


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).


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