Influence of Silica Nanoparticles on Mechanical Properties of HPC

2016 ◽  
Vol 825 ◽  
pp. 81-84
Author(s):  
Lenka Laiblová ◽  
Tomáš Vlach ◽  
Anuj Kumar ◽  
Alexandru Chira

Nanotechnology proved to be a useful tool that can significantly improve the mechanical properties of ultra-high performance concrete. This paper presents the results of a long-term research which is focused on the influence of SiO2 nanoparticles on the mechanical properties of high performance concrete. Three types of HPC specimens with a weight content of 0%, 1% and respectively 3% silica nanoparticle were prepared for flexural and compressive tests. SEM analysis was done in order to understand the effect of silica nanoparticle dispersion inside the cement matrix. The aim of this paper was to investigate the nanoparticles dispersion and how it affects concrete’s mechanical properties.

Buildings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 11 ◽  
Author(s):  
Piotr Smarzewski

Waste foundry sand (WFS) is a ferrous and non-ferrous foundry industry by-product, produced in the amount of approximately 700 thousand tons annually in Poland and it is estimated that only a small percentage of this waste is recycled. The study used WFS to produce ultra-high performance concrete (UHPC) as a partial substitute for quartz sand. It was replaced with WFS levels of 0%, 5%, 10%, and 15% by weight of quartz sand content. The UHPC mixtures were produced and tested to determine the compressive strength, flexural strength, splitting tensile strength as well as the modulus of elasticity at 28, 56, and 112 days. Scanning electron microscope (SEM) analysis was done to identify the presence of various compounds and micro-cracks in UHPC with WFS. The results revealed an increase as well as an insignificant decrease in the mechanical properties up to 5% and 10% WFS replacement, respectively. These studies also prove improvement in the microstructure of UHPC up to a 5% WFS level. In all the tested properties in this work, 5% WFS was found to be an apt substitute for quartz sand.


2016 ◽  
Vol 714 ◽  
pp. 107-110
Author(s):  
Tomáš Vlach ◽  
Lenka Laiblová ◽  
Anuj Kumar ◽  
Alexandru Chira

The aim of this work is to study the influence of carbon nanotubes in the cement matrix of high performance concrete (HPC) on flexural and compressive strength. This paper describes the samples preparation for the flexural and compression experimental tests. In order to understand the effect of carbon nanotubes in the cement matrix, a scanning electron microscope (SEM) analysis was carried out. It was reported after experimental tests that an improper dispersion of nanoparticles can have a negative influence on the mechanical properties. The dispersion of carbon nanotubes in the cement matrix is the most important aspect in order to attain the predicated influence on the mechanical properties.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2455
Author(s):  
Jiayuan He ◽  
Weizhen Chen ◽  
Boshan Zhang ◽  
Jiangjiang Yu ◽  
Hang Liu

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.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4304
Author(s):  
Markssuel Teixeira Marvila ◽  
Afonso Rangel Garcez de de Azevedo ◽  
Paulo R. de de Matos ◽  
Sergio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira

This review article proposes the identification and basic concepts of materials that might be used for the production of high-performance concrete (HPC) and ultra-high-performance concrete (UHPC). Although other reviews have addressed this topic, the present work differs by presenting relevant aspects on possible materials applied in the production of HPC and UHPC. The main innovation of this review article is to identify the perspectives for new materials that can be considered in the production of novel special concretes. After consulting different bibliographic databases, some information related to ordinary Portland cement (OPC), mineral additions, aggregates, and chemical additives used for the production of HPC and UHPC were highlighted. Relevant information on the application of synthetic and natural fibers is also highlighted in association with a cement matrix of HPC and UHPC, forming composites with properties superior to conventional concrete used in civil construction. The article also presents some relevant characteristics for the application of HPC and UHPC produced with alkali-activated cement, an alternative binder to OPC produced through the reaction between two essential components: precursors and activators. Some information about the main types of precursors, subdivided into materials rich in aluminosilicates and rich in calcium, were also highlighted. Finally, suggestions for future work related to the application of HPC and UHPC are highlighted, guiding future research on this topic.


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 405-408 ◽  
pp. 2847-2850
Author(s):  
Wu Jian Long ◽  
Wei Lun Wang ◽  
Qi Ling Luo ◽  
Bi Qin Dong

In order to understand the influence of mixture parameters on ultra-high strength self-consolidating concrete (UHS-SCC) behaviour, an experimental design was carried out in this investigation. In total, 19 SCC mixtures were prepared to determine several key responses that affect the slump flow and compressive strength of UHS-SCC. The statistical models derived from the factorial design approach can be used to quantify the effect of mixture parameters and their coupled effects on fresh and mechanical properties of SCC.


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