Alkali-silica reaction expansions in high-performance and normal-strength cement grouts reinforced with steel and synthetic fibers

2005 ◽  
Vol 41 (1) ◽  
pp. 87-94
Author(s):  
R. H. Haddad ◽  
A. Qudah
Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 427
Author(s):  
Pavlina Mateckova ◽  
Vlastimil Bilek ◽  
Oldrich Sucharda

High-performance concrete (HPC) is subjected to wide attention in current research. Many research tasks are focused on laboratory testing of concrete mechanical properties with specific raw materials, where a mixture is prepared in a relatively small amount in ideal conditions. The wider utilization of HPC is connected, among other things, with its utilization in the construction industry. The paper presents two variants of HPC which were developed by modification of ordinary concrete used by a precast company for pretensioned bridge beams. The presented variants were produced in industrial conditions using common raw materials. Testing and comparison of basic mechanical properties are complemented with specialized tests of the resistance to chloride penetration. Tentative expenses for normal strength concrete (NSC) and HPC are compared. The research program was accomplished with a loading test of model experimental pretensioned beams with a length of 7 m made of ordinarily used concrete and one variant of HPC. The aim of the loading test was to determine the load–deformation diagrams and verify the design code load capacity calculation method. Overall, the article summarizes the possible benefits of using HPC compared to conventional concrete.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarmad Shafeeq Abdulqader ◽  
Asmaa Ali Ahmed ◽  
Nawfal Shihab Ahmed

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.


2011 ◽  
Vol 57 (4) ◽  
pp. 357-371 ◽  
Author(s):  
S. Gopinath ◽  
A. Ramachandra Murthy ◽  
D. Ramya ◽  
Nagesh R. Iyer

Abstract This paper presents the details of optimized mix design for normal strength and high performance concrete using particle packing method. A critical review of mix design methods have been carried out for normal strength concrete using American Concrete Institute (ACI) and Bureau of Indian Standards (BIS) methods highlighting the similarities and differences towards attaining a particular design compressive strength. Mix design for M30 and M40 grades of concrete have been carried out using ACI, BIS and particle packing methods. Optimization of concrete mix has been carried out by means of particle packing method using EMMA software, which employs modified Anderson curve to adjust the main proportions. Compressive strength is evaluated for the adjusted proportions and it is observed that the mixes designed by particle packing method estimates compressive strength closer to design compressive strength. Further, particle packing method has been employed to optimize the ingredients of high performance concrete and experiments have been carried out to check the design adequacy of the desired concrete compressive strength.


2019 ◽  
Vol 271 ◽  
pp. 07008
Author(s):  
William Toledo ◽  
Leticia Davila ◽  
Ahmed Al-Basha ◽  
Craig Newtson ◽  
Brad Weldon

This paper investigates the shrinkage and thermal effects of an ultra-high performance concrete (UHPC) mixture proposed for use as an overlay material for concrete bridge decks. In this study, early-age and longer-term shrinkage tests were performed on the locally produced UHPC. Thermal and shrinkage effects in normal strength concrete slabs overlaid with UHPC were also observed. Early-age shrinkage testing showed that approximately 55% of the strain occurred in the plastic state and may not contribute to bond stresses since the elastic modulus of the UHPC should be small at such early ages. Thickness of the substrate and amount of reinforcing steel were important factors for shrinkage in the slabs. The thickest slab experienced greater shrinkage than thinner slabs. Comparing this slab to a thinner slab with the same reinforcement indicated that reinforcement ratio is more important than the area of steel.


2017 ◽  
Vol 259 ◽  
pp. 70-74
Author(s):  
Milan Holý

This paper deals with the roof structural system using prestressed girders made of ultra-high performance concrete (UHPC). One of the aims of this study is to verify whether the option of the UHPC girders could be under certain boundary conditions competitive with the commonly used construction materials. Due to its high strength, UHPC enables the design of the structural elements with the high load bearing capacity and with smaller slenderness compared to normal strength concrete elements. The price of UHPC is currently still very high compared to the normal strength concretes or steel. Therefore, its use for the usual designed structures does not recently seem too economically attractive. The effect of material savings is nonnegligible in the case, that a self-weight of the structure forms dominant component of the total load. In addition to the high strength, UHPC has very high resistance to environmental influences. It is therefore likely, that UHPC could be advantageously applied e.g. for the roofing of industrial buildings of chemical plants with high aggressive environments, because there are high demands on the life cycle of the structure.


2019 ◽  
Vol 22 (7) ◽  
pp. 1727-1738 ◽  
Author(s):  
Masoud Pourbaba ◽  
Hamed Sadaghian ◽  
Amir Mirmiran

In this research, the flexural and shear behavior of five locally developed ultra-high-performance fiber-reinforced concrete beams was experimentally investigated. Four-point loading tests were carried out on concrete specimens which were further compared with five normal-strength concrete beams constructed at the laboratory. The objective of this study is to assess the flexural and shear behavior of ultra-high-performance fiber-reinforced concrete beams and compare them with that of normal-strength beams and available equations in the literature. Results indicate underestimation of shear (up to 2.71 times) and moment capacities (minimum 1.27 times, maximum 3.55 times) by most of the equations in beams with low-reinforcement ratios. Finally, results reveal that the experimental flexural and shear capacities of ultra-high-performance fiber-reinforced concrete specimens are up to 3.5 times greater than their normal-strength counterpart specimens.


2014 ◽  
Vol 638-640 ◽  
pp. 1503-1507
Author(s):  
Ting Zhang ◽  
Yi Tang Zhou ◽  
Luo Ke Li ◽  
Xiu Ying Fan

Emergence of commodity concrete and pumping concrete is a major development of modern concrete technology, it has high efficiency, high homogeneity and good environmental effects, etc. But, use of modern high performance concrete make the difficulty of controlling the early cracks increased, considering this problem, use of polypropylene fibers to test concrete shrinkage cracks, come to regularity of polypropylene fiber affect concrete shrinkage cracks early, in order to serve the synthetic fibers used in concrete better.


Sign in / Sign up

Export Citation Format

Share Document