scholarly journals Long Term Behavior of Ultra High-Performance Concrete

2021 ◽  
pp. 36-54
Author(s):  
Zeinab A. Etman ◽  
Noha M. Soliman ◽  
Mahmoud M. Abou Raia
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Fine Sand ◽  
Time Behavior ◽  
Quartz Powder ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
Fineness Modulus

Ultra-High-Performance Concrete (UHPC) is one of the important types of concrete technology breakthroughs in the 21st century. It achieved high results of mechanical properties, durability (resistance fire) and bonding strength. The aim of paper is to evaluate the long-time behavior of UHPC. The main variables were finesse modulus of sand, crushed quartz powder, fly ash and metakaolin and methods of curing (water& hot).The sand with different fineness modulus(3.2, 2.36 and 1.9) were used, Crushed quartz powder with ratio (10%, 20% and 30%) as a replacement of sand was used. Fly ash and metakaolin, with of (10%, 20%, 30 and 40%) and (5%, 10% and 15%) as a replacement of cement; respectively. The effect of these variables on the mechanical properties (compressive, tensile, flexural strength) at different ages. Also, the drying shrinkage strain was evaluated. The results showed that using and with fineness modulus (1.9), 20% ratio of crushed quartz powder to fine sand (CQ/S), 20% of fly ash to cement (FA/C) and 5% of metakaolin to cement (MK/C) give the best proportions of UHPC. The compressive strength for this mix was 900 kg/ cm2 .

Research Status and Prospects on the Ultra High Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 1506-1508
Author(s):  
Jie Sun
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
The Sustainable Development ◽  
Volume Stability ◽  
Existing Problems ◽  
Practical Engineering

The ultra high performance concrete is a new cement-based composite material with ultra-high mechanical properties, excellent durability and excellent volume stability. In this paper, research and application of the ultra high performance concrete at home and abroad at present was introduced, existing problems of the ultra high performance concrete applied to much practical engineering were pointed out. Finally, the prospects of ultra high performance concrete were analyzed and the ultra high performance concrete is inevitable result of the sustainable development of modern concrete technology.

scholarly journals Use of Waste from Granite Gang Saws to Manufacture Ultra-High Performance Concrete Reinforced with Steel Fibers

2021 ◽  
Vol 11 (4) ◽  
pp. 1764
Author(s):  
Fernando López Gayarre ◽  
Jesús Suárez González ◽  
Iñigo Lopez Boadella ◽  
Carlos López-Colina Pérez ◽  
Miguel Serrano López
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Elasticity Modulus ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Fiber Reinforced Concrete ◽  
Final Conclusion ◽  
Quartz Powder ◽  
Steel Fiber Reinforced Concrete ◽  
Ultra High Performance Concrete

The purpose of this study is to analyze the feasibility of using the ultra-fine waste coming from the granite cutting waste gang saws (GCW-GS) to manufacture ultra-high performance, steel-fiber reinforced concrete (UHPFRC). These machines cut granite blocks by abrasion using a steel blade and slurry containing fine steel grit. The waste generated by gang saws (GCW-GS) contains up to 15% Fe2O3 and up to 5% CaO. This is the main difference from the waste produced by diamond saws (GCW-D). Although this waste is available in large quantities, there are very few studies focused on recycling it to manufacture any kind of concrete. In this study, the replaced material was the micronized quartz powder of natural origin used in the manufacture of UHPRFC. The properties tested include workability, density, compressive strength, elasticity modulus, flexural strength, and tensile strength. The final conclusion is that this waste can be used to manufacture UHPFRC with a better performance than that from diamond saws given that there is an improvement of their mechanical properties up to a replacement of 35%. Even for higher percentages, the mechanical properties are within values close to those of control concrete with small decreases.

scholarly journals Use of Waste from Granite Gang Saws to Manufacture Ultra-High Performance Concrete Reinforced with Steel Fibres

2021 ◽  
Author(s):  
Fernando López Gayarre ◽  
Jesús Suárez González ◽  
Iñigo Lopez Boadella ◽  
Carlos López-Colina Pérez ◽  
Miguel Serrano López
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Elasticity Modulus ◽  
High Performance Concrete ◽  
Final Conclusion ◽  
Quartz Powder ◽  
Ultra High Performance Concrete ◽  
Steel Fibre Reinforced Concrete ◽  
Indirect Tensile ◽  
Iron And Calcium

The purpose of this study is to analyse the feasibility of using waste from granite gang saws (GCW-GS) to manufacture ultra-high performance, steel-fibre reinforced concrete (UHPFRC). These machines cut granite blocks by abrasion using a steel blade and slurry containing fine steel grit. The waste generated by gang saws (GCW-GS) contains up to 15% Fe2O3 and up to 5% CaO. This is the main difference from the waste produced by diamond saws (GCW-D). Consequently, the second objective of this study is to compare the results of the waste obtained with gang saws with that from diamond saws, in order to determine the influence of iron and calcium oxides. The waste from cutting granite with gang saws was used in different percentages to replace micronized quartz powder of natural origin in the manufacture of UHPRFC. All the test specimens were analysed to determine their compressive strength, elasticity modulus, flexural strength and indirect tensile strength. The final conclusion is that wastes from both gang saws and diamond saws can be used to manufacture UHPFRC with an improvement in the mechanical properties up to a 35% replacement. The results for GCW-GS are better, mainly due to the pozzolanic effect of the iron dioxide. For higher percentage replacements the mechanical properties are close to the control concrete with small decreases.

scholarly journals The Mechanical Properties and Damage Evolution of UHPC Reinforced with Glass Fibers and High-Performance Polypropylene Fibers

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2455
Author(s):  
Jiayuan He ◽  
Weizhen Chen ◽  
Boshan Zhang ◽  
Jiangjiang Yu ◽  
Hang Liu
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Damage Evolution ◽  
High Performance ◽  
High Performance Concrete ◽  
Glass Fibers ◽  
Ultra High Performance Concrete ◽  
Concrete Damaged Plasticity ◽  
The Difference ◽  
Experimental Values

Due to the sharp and corrosion-prone features of steel fibers, there is a demand for ultra-high-performance concrete (UHPC) reinforced with nonmetallic fibers. In this paper, glass fiber (GF) and the high-performance polypropylene (HPP) fiber were selected to prepare UHPC, and the effects of different fibers on the compressive, tensile and bending properties of UHPC were investigated, experimentally and numerically. Then, the damage evolution of UHPC was further studied numerically, adopting the concrete damaged plasticity (CDP) model. The difference between the simulation values and experimental values was within 5.0%, verifying the reliability of the numerical model. The results indicate that 2.0% fiber content in UHPC provides better mechanical properties. In addition, the glass fiber was more significant in strengthening the effect. Compared with HPP-UHPC, the compressive, tensile and flexural strength of GF-UHPC increased by about 20%, 30% and 40%, respectively. However, the flexural toughness indexes I5, I10 and I20 of HPP-UHPC were about 1.2, 2.0 and 3.8 times those of GF-UHPC, respectively, showing that the toughening effect of the HPP fiber is better.

scholarly journals Ultra-high-performance concrete with local high unburned carbon fly ash

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 38-47
Author(s):  
Joaquín Abellán García ◽  
Nancy Torres Castellanos ◽  
Jaime Antonio Fernandez Gomez ◽  
Andres Mauricio Nuñez Lopez
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
Unburned Carbon ◽  
High Tech ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Cost

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.

scholarly journals Determination of Axial Capacity for Enhanced Normal and Ultra - High Performance Concrete Columns

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarmad Shafeeq Abdulqader ◽  
Asmaa Ali Ahmed ◽  
Nawfal Shihab Ahmed
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Peak Load ◽  
Concrete Cover ◽  
Ultra High Performance Concrete ◽  
Concrete Technology ◽  
Compression Load ◽  
Axial Capacity ◽  
Load Carrying ◽  
Normal Strength

Abstract Concrete Technology has been developing for more than a century. One of the most exceptional achievements in concrete technology is the evolving of Ultra-High Performance Concrete (UHPC) which has been a research focus in a wide applications diversity. In this paper, an experimental work has been carried out for investigating the transverse and longitudinal reinforcements’ variation influence on the axial capacity of UHPC columns. Eight columns (five UHPC columns and three Normal Strength Concrete (NSC) columns) have been poured and tested under a concentric axial compression load till a failure is reached. Then, the results are reported herein. The experimental results show that UHPC columns failed in a controlled manner and no concrete chips or a concrete cover spalling are observed. Also, the longitudinal reinforcements have not buckled away beyond the peak load because of the presence of the reinforcing steel fibers in UHPC. Correspondingly, the steel ties spacing proportionally affects the load carrying capacity of columns as presented hereinafter.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

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