Triaxial strength and failure criterion of plain high-strength and high-performance concrete before and after high temperatures

Iron tailing powder (ITP) is considered to have the potential to replace cement to manufacture ultra-high-performance concrete (UHPC). However, the performance of UHPC with the addition of ITP after exposure to high temperatures is more complex. This investigation prepares seven UHPC formulations by introducing different contents of ITP and investigates the mechanical behavior (residual strength), bound water content, and microstructural properties (crystalline and amorphous phases, chemical structure, and morphology) of UHPC subjected to elevated temperatures. The experimental results show that the addition of ITP postpones the spalling of concrete when exposed to high temperatures. The concrete incorporating 15% ITP maintains 53.8% of its original strength at 800°C, unlike the concrete without ITP that maintains 31.6% of its original strength. The addition of ITP increases the number of micropores/cracks in concrete and helps release the vapor pressure caused by water evaporation. The findings of this investigation highlight the potential application of ITP for future UHPC design and manufacture.

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Bestimmung der Dauerhaftigkeit von Hochleistungsbeton mit Hilfe des CDF-Tests / Determination of the durability of high performance concrete by means of CDF-test

Restoration of Buildings and Monuments ◽

10.1515/rbm-1999-5340 ◽

1999 ◽

Vol 5 (1) ◽

pp. 29-40

Author(s):

R. Krumbach ◽

U. Schmelter ◽

K. Seyfarth

Keyword(s):

Frost Resistance ◽

High Strength Concrete ◽

High Performance ◽

High Performance Concrete ◽

High Strength ◽

Strength Concrete ◽

Factors Influencing

Abstract Variable obsen>ations concerning frost resistance of high performance concrete have been made. The question arises which are the decisive factors influencing durability under the action of frost and de-icing salt. The proposed experiments are to be carried out in cooperation with F.A.- Finger - Institute of Bauhaus University Weimar. The aim of this study is to determine possible change of durability of high strength concrete, and to investigate the origin thereof. Measures to reduce the risk of reduced durability have to be found.

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Hugoniot Data and Equation of State Parameters for an Ultra-High Performance Concrete

Journal of Dynamic Behavior of Materials ◽

10.1007/s40870-021-00315-6 ◽

2021 ◽

Author(s):

C. Sauer ◽

F. Bagusat ◽

M.-L. Ruiz-Ripoll ◽

C. Roller ◽

M. Sauer ◽

...

Keyword(s):

Equation Of State ◽

High Performance ◽

High Performance Concrete ◽

Applied Pressure ◽

High Strength ◽

Parameter Study ◽

Ultra High Performance Concrete ◽

Data Set ◽

Shock Response ◽

Particle Velocities

AbstractThis work aims at the characterization of a modern concrete material. For this purpose, we perform two experimental series of inverse planar plate impact (PPI) tests with the ultra-high performance concrete B4Q, using two different witness plate materials. Hugoniot data in the range of particle velocities from 180 to 840 m/s and stresses from 1.1 to 7.5 GPa is derived from both series. Within the experimental accuracy, they can be seen as one consistent data set. Moreover, we conduct corresponding numerical simulations and find a reasonably good agreement between simulated and experimentally obtained curves. From the simulated curves, we derive numerical Hugoniot results that serve as a homogenized, mean shock response of B4Q and add further consistency to the data set. Additionally, the comparison of simulated and experimentally determined results allows us to identify experimental outliers. Furthermore, we perform a parameter study which shows that a significant influence of the applied pressure dependent strength model on the derived equation of state (EOS) parameters is unlikely. In order to compare the current results to our own partially reevaluated previous work and selected recent results from literature, we use simulations to numerically extrapolate the Hugoniot results. Considering their inhomogeneous nature, a consistent picture emerges for the shock response of the discussed concrete and high-strength mortar materials. Hugoniot results from this and earlier work are presented for further comparisons. In addition, a full parameter set for B4Q, including validated EOS parameters, is provided for the application in simulations of impact and blast scenarios.

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Abrasion Resistance of Ultra-High-Performance Concrete for Railway Sleepers

Urban Rail Transit ◽

10.1007/s40864-021-00145-8 ◽

2021 ◽

Author(s):

Ariful Hasnat ◽

Nader Ghafoori

Keyword(s):

Prestressed Concrete ◽

Abrasion Resistance ◽

High Performance ◽

High Performance Concrete ◽

High Strength ◽

Positive Influence ◽

Cementitious Material ◽

Partial Replacement ◽

Fine Aggregate ◽

Ultra High Performance Concrete

AbstractThis study aimed to determine the abrasion resistance of ultra-high-performance concretes (UHPCs) for railway sleepers. Test samples were made with different cementitious material combinations and varying steel fiber contents and shapes, using conventional fine aggregate. A total of 25 UHPCs and two high-strength concretes (HSCs) were selected to evaluate their depth of wear and bulk properties. The results of the coefficient of variation (CV), relative gain in abrasion, and abrasion index of the studied UHPCs were also obtained and discussed. Furthermore, a comparison was made on the resistance to wear of the selected UHPCs with those of the HSCs typically used for prestressed concrete sleepers. The outcomes of this study revealed that UHPCs displayed excellent resistance against abrasion, well above that of HSCs. Amongst the utilized cementitious material combinations, UHPCs made with silica fume as a partial replacement of cement performed best against abrasion, whereas mixtures containing fly ash showed the highest depth of wear. The addition of steel fibers had a more positive influence on the abrasion resistance than it did on compressive strength of the studied UHPCs.

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Accelerated testing of super lightweight UHPC waffle deck under heavy vehicle simulator

Bridge Structures ◽

10.3233/brs-200176 ◽

2021 ◽

Vol 16 (2-3) ◽

pp. 61-74

Author(s):

Sahar Ghasemi ◽

Amir Mirmiran ◽

Yulin Xiao ◽

Kevin Mackie

Keyword(s):

High Performance ◽

Failure Modes ◽

High Performance Concrete ◽

High Strength ◽

Heavy Vehicle ◽

Wheel Load ◽

Element Analysis ◽

Vehicle Simulator ◽

Pavement Testing ◽

Heavy Vehicle Simulator

A super lightweight deck can enhance load rating and functionality of a bridge, especially those identified as structurally deficient. This study was aimed to develop and experimentally validate a novel bridge deck as an ultra-lightweight low-profile waffle slab of ultra-high-performance concrete (UHPC) with either carbon fiber reinforced polymer (CFRP) or high strength steel (HSS) reinforcement. The proposed system lends itself to accelerated bridge construction, rapid deck replacement in bridges with load restrictions, and bridge widening applications without the need to replace girders. Performance and failure modes of the proposed deck were initially assessed through extensive lab experiments and finite element analysis, which together confirmed that the proposed deck panel meets the AASHTO LRFD requirements. The proposed deck system is not susceptible to punching shear of its thin slab and fails in a rather ductile manner. To evaluate its long-term performance, the system was further tested under the dynamic impact of wheel load at the Accelerated Pavement Testing (APT) facility of the Florida Department of Transportation using a Heavy Vehicle Simulator (HVS).

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Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽

10.3390/buildings11020063 ◽

2021 ◽

Vol 11 (2) ◽

pp. 63

Author(s):

Anna L. Mina ◽

Michael F. Petrou ◽

Konstantinos G. Trezos

Keyword(s):

Reinforced Concrete ◽

High Performance ◽

High Performance Concrete ◽

High Strength ◽

Fiber Reinforced Concrete ◽

Steel Fibers ◽

Fiber Reinforced ◽

Depth Of Penetration ◽

Projectile Impact ◽

High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

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