Time Progress of Compressive Strength of High Performance Concrete

2013 ◽  
Vol 486 ◽  
pp. 167-172 ◽  
Author(s):  
Ondřej Holčapek ◽  
Filip Vogel ◽  
Tomáš Vavřiník ◽  
Martin Keppert

Development in the field of concrete engineering is increasingly focused on the practical application of high performance concrete (HPC) or ultra-high performance concrete (UHPC) in construction practise. Newly developed kings of concrete are newly using in transport and building structures. The process of hydration of hydraulic binders based on Portland cement doesn ́t stop after 28 days, when the test of compressive strength take place, but it ́s a long time process that takes for many months. For design we use the values of strength of 28 days. This paper explorers how does the long-term development of compressive strength of HPC runs. The composition of HPC is significantly different from the common concrete lower strength classes. The question of the influence of additives, filler on microsilica based, silica flour to the time development of compressive strength is being explored in this paper. There is also recorded the influence of curing condition of the test specimens to the compressive strength. The age of testing samples starts at a very early ages 1, 3, 7, 21, 28, 45, 90 and 180 days. The strength in uniaxial compression was measured on cubes with dimension 100 mm.

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1829
Author(s):  
Gang Ling ◽  
Zhonghe Shui ◽  
Xu Gao ◽  
Tao Sun ◽  
Rui Yu ◽  
...  

In this research, iron ore tailing (IOT) is utilized as the cementitious material to develop an eco-friendly ultra-high performance concrete (UHPC). The UHPC mix is obtained according to the modified Andreasen and Andersen (MAA) packing model, and the applied dosage of IOT is 10%, 20%, and 30% (by weight), respectively. The calculated packing density of different mixtures is consistent with each other. Afterwards, the fresh and hardened performance of UHPC mixtures with IOT are evaluated. The results demonstrate that the workability of designed UHPC mixtures is increased with the incorporation of IOT. The heat flow at an early age of designed UHPC with IOT is attenuated, the compressive strength and auto shrinkage at an early age are consequently reduced. The addition of IOT promotes the development of long-term compressive strength and optimization of the pore structure, thus the durability of designed UHPC is still guaranteed. In addition, the ecological estimate results show that the utilization of IOT for the UHPC design can reduce the carbon emission significantly.


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 (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.


2016 ◽  
Vol 827 ◽  
pp. 215-218 ◽  
Author(s):  
David Čítek ◽  
Milan Rydval ◽  
Jiří Kolísko

Research in the Ultra-High Performance Concrete applications field is very important. Current experiences shows that the structure design should be optimize due to relatively new fine-grained cement-based Hi-Tech material with excellent mechanical and durability properties. It is not sure if some of the volumetric changes like creep or shrinkage has or has not an impact on an advantage for the construction and for the structure design. The effect of the shrinkage and creep of common used concretes are well known and well described at publications but the effect of volumetric changes of the UHPC is mostly unknown because of the fact that some of experimental tests are long term and the development of UHPC is still in its basics. A lot of works are focused on a basic mechanical properties and durability tests.


2013 ◽  
Vol 357-360 ◽  
pp. 825-828
Author(s):  
Su Li Feng ◽  
Peng Zhao

The test in order to obtain liquidity, higher intensity ultra-high performance concrete(UHPC), in the course of preparation, high intensity quartz sand to replace the ordinary sand,reasonable mixture ratio control low water-cement ratio,the incorporation of part of the test piece ofsteel fibers, produced eight specimens . In the ordinary molding and the standard conservation 28d thecase, the ultra-high-performance concrete compressive strength of more than 170MPa.Thepreparation of the test method and test results will provide the basis for further study of the law of themechanical properties of ultra high strength properties of concrete.


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