scholarly journals Study on Optimization of Working Performance of Ultra High Performance Concrete

2020 ◽  
Vol 198 ◽  
pp. 01005
Author(s):  
Wang Shengyu ◽  
Zhan Yijian
Keyword(s):  
Water Consumption ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
High Sensitivity ◽  
Ultra High Performance Concrete ◽  
Influence Of Water ◽  
Binder Ratio ◽  
Viscosity Reducer ◽  
Physical And Chemical

The water binder ratio is a key parameter in the mix design of ultra-high performance concrete. Aiming at the high sensitivity of ultra-high performance concrete to water consumption, the influence of water consumption on the performance of ultra-high performance concrete was studied in a narrow range. The compatibility ratio of raw materials of ultra-high performance concrete can be adjusted, but the space is small, so we try to improve the fluidity of concrete by physical and chemical means. The experimental results show that the fluidity of concrete increases slightly with the addition of glass beads, but the flexural properties of the concrete are adversely affected. With the addition of viscosity reducer, the workbility of concrete increases, but the compressive strength decreases.

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
Keyword(s):  
Compressive Strength ◽  
Environmental Impact ◽  
Young’S Modulus ◽  
High Performance ◽  
High Performance Concrete ◽  
Young's Modulus ◽  
Ultra High Performance Concrete ◽  
Aeolian Sand ◽  
Binder Ratio ◽  
Water Binder Ratio

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.

Mechanical Properties and Durability of Ultra-High Performance Concrete Incorporating Coarse Aggregate

2014 ◽  
Vol 629-630 ◽  
pp. 96-103 ◽  
Author(s):  
Juan Yang ◽  
Gai Fei Peng ◽  
Yu Xin Gao ◽  
Hui Zhang
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
Coarse Aggregate ◽  
High Performance Concrete ◽  
Fresh Concrete ◽  
Raw Materials ◽  
Autogenous Shrinkage ◽  
Mineral Admixtures ◽  
Ultra High Performance Concrete ◽  
Spalling Failure

Ultra-high performance concrete (UHPC) incorporating coarse aggregate was prepared with common raw materials. Fresh concrete had excellent good workability with slump of 265 mm and slump spread of 673 mm. Compressive strength of UHPC at 56 d reached 150 MPa. However, UHPC exhibited high brittleness in terms of spalling failure which occurred during compression loading.The ratio of splitting tensile strength to compressive strength of about 1/18 and the ratio of flexural strength to compressive strength of about 1/14 at 56 d were also associated with the brittleness of UHPC in this research. Mineral admixtures and fluidity of fresh concrete influenced compressive strength of UHPC significantly. Moreover, UHPC had excellent permeation-related durability but considerable shrinkage. Autogenous shrinkage of UHPC was less than half of free shrinkage, for which the reason is unknown and needs further research.

scholarly journals Matrix Optimization of Ultra High Performance Concrete for Improving Strength and Durability

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6944
Author(s):  
Julio A. Paredes ◽  
Jaime C. Gálvez ◽  
Alejandro Enfedaque ◽  
Marcos G. Alberti
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
Mercury Intrusion Porosimetry ◽  
High Performance Concrete ◽  
Silica Sand ◽  
Nano Silica ◽  
Ultra High Performance Concrete ◽  
Matrix Optimization ◽  
Binder Ratio ◽  
Strength And Durability

This paper seeks to optimize the mechanical and durability properties of ultra-high performance concrete (UHPC). To meet this objective, concrete specimens were manufactured by using 1100 kg/m3 of binder, water/binder ratio 0.20, silica sand and last generation of superplasticizer. Silica fume, metakaolin and two types of nano silica were used for improving the performances of the concrete. Additional mixtures included 13 mm long OL steel fibers. Compressive strength, electrical resistivity, mercury intrusion porosimetry tests, and differential and thermogravimetric thermal analysis were carried out. The binary combination of nano silica and metakaolin, and the ternary combination of nano silica with metakaolin and silica fume, led to the best performances of the UHPC, both mechanical and durable performances.

Combined Influence of Expansive and Shrinkage Reducing Admixtures on the Shrinkage Behavior of Ultra-High Performance Concrete

2011 ◽  
Vol 488-489 ◽  
pp. 242-245 ◽  
Author(s):  
Jung Jun Park ◽  
Doo Youl Yoo ◽  
Sung Wook Kim ◽  
Young Soo Yoon
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Shrinkage Strain ◽  
Reducing Agents ◽  
Reinforcing Bars ◽  
Ultra High Performance Concrete ◽  
Free Shrinkage ◽  
Shrinkage Cracks ◽  
Binder Ratio ◽  
Shrinkage Reducing Admixtures

Since ultra-high performance cementitious composite (UHPCC) exhibits remarkable compressive strength and ductility, its application for structural member provides significant reduction of the section. The use of low water-to-binder ratio and admixtures with high fineness induce large shrinkage strain, leading to the possibility of large occurrence of shrinkage cracks due to the restraints of the form and reinforcing bars. Therefore, this study admixes a combination of expansive and shrinkage reducing agents as a solution to reduce the shrinkage of UHPCC. The eventual appropriateness is computed to evaluate the free shrinkage and restrained shrinkage behaviors. From the test results, the admixing of a combination of expansive and shrinkage reducing agents is seen to achieve a reduction of the free shrinkage by 30% to 50% at 28 days and a reduction of the strain of the external steel by about 19%.

A review on ultra high performance concrete: Part I. Raw materials and mixture design

2015 ◽  
Vol 101 ◽  
pp. 741-751 ◽  
Author(s):  
Caijun Shi ◽  
Zemei Wu ◽  
Jianfan Xiao ◽  
Dehui Wang ◽  
Zhengyu Huang ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Mixture Design ◽  
Ultra High Performance Concrete ◽  
Concrete Part

scholarly journals Synthesis of Modified Polycarboxylate and Its Application in Ultra-High Performance Concrete

2021 ◽  
Vol 8 ◽  
Author(s):  
Shuncheng Xiang ◽  
Yansheng Tan ◽  
Yingli Gao
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
Chain Transfer ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Synthesis Method ◽  
Drying Shrinkage ◽  
Polymerization Reaction ◽  
Ultra High Performance Concrete ◽  
Initiation System

Modified polyurethane prepolymer was prepared using the segmental synthesis method. Then, pectiniform polycarboxylate was synthesized at normal temperature in the complex initiation system of H2O2, APS, sodium bisulfite, Vc, and Rongalit according to the free radical polymerization reaction mechanism, using TPEG, AA, and PEG as raw materials and TGA as the chain transfer agent. Compared with commercial Sika polycarboxylate, its flowability, strength, drying shrinkage, and auto-shrinkage were studied. The experimental results show that the synthesized polycarboxylate could be better dispersed. Adding silica fume can enhance the compressive strength of ultra-high performance concrete (UHPC), while slag may decline its strength. By incorporating slag and silica fume, the drying shrinkage of UHPC was reduced, but its auto-shrinkage was increased.

scholarly journals Matrix Optimization of Ultra High Performance Concrete for Improving Strength and Durability

2021 ◽  
Author(s):  
Julio Paredes ◽  
Jaime C. Gálvez ◽  
Alejandro Enfedaque ◽  
Marcos G. Alberti
Keyword(s):  
Silica Fume ◽  
High Performance ◽  
Mercury Intrusion Porosimetry ◽  
High Performance Concrete ◽  
Silica Sand ◽  
Nano Silica ◽  
Ultra High Performance Concrete ◽  
Matrix Optimization ◽  
Binder Ratio ◽  
Strength And Durability

This paper seeks to optimize the mechanical and durability properties of ultra-high performance concrete (UHPC). To meet this objective, concrete specimens were manufactured by using 1,100 kg/m3 of binder, water/binder ratio 0.20, silica sand and last generation of superplasticizer. Silica fume, metakaolin and two types of nano silica were used for improving the performances of the concrete. Additional mixtures included 13mm long OL steel fibers. Compressive strength, electrical resistivity, mercury intrusion porosimetry tests and differential and thermogravimetric thermal analysis were carried out. The binary combination of nano silica and metakaolin, and the ternary combination of nano silica with metakaolin and silica fume, led to the best performances of the UHPC, both mechanical and durable performances.

scholarly journals Advanced composite structure combining Ultra high performance concrete with normal reinforced concrete

2019 ◽  
Vol 278 ◽  
pp. 03004
Author(s):  
Xiangguo Wu
Keyword(s):  
Reinforced Concrete ◽  
Material Properties ◽  
Composite Structure ◽  
Composite Structures ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Constitutive Relations ◽  
Ultra High Performance Concrete ◽  
Advanced Composite

Ultra high performance concrete (UHPC), one of the newest cementitious composites, demonstrates superior ductility with high strength and durability, which has gained the attention of researchers and engineers since it was successfully developed. Considering its superior ductility and durability, UHPC is a good alternative material for forming a advanced composite structure with normal reinforced concrete (RC) or prestressed concrete. The material properties are critical for its application in composite structures, so in this chapter, material properties of UHPC, such as constitute raw materials, mechanical properties, durability and several constitutive relations from several standards are firstly introduced. The basic concepts of advanced UHPC-RC composite structures, such as UHPC-RC composite beam, composite column, composite wall, etc, are introduced finally.

Development of Ultra High Performance Concrete Using Fly Ash

2020 ◽  
Vol 987 ◽  
pp. 33-38
Author(s):  
Rudolf Hela ◽  
Lenka Bodnárová
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Experimental Work ◽  
High Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Economic Cost ◽  
Ultra High Performance Concrete ◽  
Secondary Raw Materials ◽  
Successful Design

The experimental work presented in this article examines the possibility of lowering the economic cost of UHPC. The UHPC were designed using the Linear Packing Density Model. After 7 days, the UHPC compressive strength exceeded 120 MPa. Level of compressive strength after 90 days reaching 150 MPa had been obtained with a lower dose of cement (700 kg/m3) and with the use of secondary raw materials (fly ash), without the use of dispersed reinforcement. The successful design and production proved that the use of secondary raw materials is possible, thereby decreasing the economic cost of UHPC production.

scholarly journals Fracture Characterization of Ultra-High Performance Concrete Notched Beams under the Influence of Different Material Factors Based on Acoustic Emission Technique

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4608
Author(s):  
Xianqiang Wang ◽  
Duo Liu ◽  
Yao Zhang ◽  
Yubo Jiao
Keyword(s):  
Acoustic Emission ◽  
Flexural Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
Fracture Characterization ◽  
Fracture Characteristics ◽  
Binder Ratio ◽  
Water Binder Ratio

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.

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