Rheology-based approach for workability characterization of high-performance concrete

2009 ◽  
Vol 36 (7) ◽  
pp. 1239-1244 ◽  
Author(s):  
Aminul Islam Laskar ◽  
Sudip Talukdar
Keyword(s):  
Yield Stress ◽  
High Performance ◽  
High Performance Concrete ◽  
Critical Issue ◽  
Energy Dissipation Rate ◽  
Plastic Viscosity ◽  
Shear Strain Rate ◽  
Test Results ◽  
Fundamental Units

Monitoring of workability is a critical issue since high-performance concrete is susceptible to small changes in mixture proportions that have a direct impact on workability and hardened properties. Test results in fundamental units such as yield stress and plastic viscosity are needed to characterize workability of high-performance concrete. In the present study, rheological properties of concretes with different workability were evaluated with a rheometer fabricated in the laboratory. Yield stress and plastic viscosity measured for various mixes were combined together with shear strain rate to obtain a single parameter, the energy dissipation rate per unit volume, which was used to develop a workability scale.

scholarly journals A simulation-based approach to evaluate objective material parameters from concrete rheometer measurements

2019 ◽  
Vol 29 (1) ◽  
pp. 130-140 ◽  
Author(s):  
Florian Gerland ◽  
Alexander Wetzel ◽  
Thomas Schomberg ◽  
Olaf Wünsch ◽  
Bernhard Middendorf
Keyword(s):  
Yield Stress ◽  
High Performance ◽  
Evaluation Method ◽  
High Performance Concrete ◽  
Direct Determination ◽  
Plastic Viscosity ◽  
Flow Properties ◽  
Fresh Sample ◽  
Material Parameters ◽  
Simulation Based

Abstract Modern concretes such as ultra-high performance concrete (UHPC) show excellent strength properties combined with favorable flow properties. However, the flow properties depend strongly on process parameters during production (temperature, humidity etc.), but also change sensitively even with slight variations in the mixture. In order to ensure desired processing of the fluidlike material and consistent process quality, the flow properties of the concrete must be evaluated quantitatively and objectively. The usual evaluation of measurements from concrete rheometers, for example of the ball probe system type, does not allow the direct determination of the objective material parameters yield stress and plastic viscosity of the sample. We developed a simulation-based method for the evaluation of rheometric measurements of fine grained high performance concretes like self-compacting concrete (SCC) and UHPC. The method is based on a dimensional analysis for ball measuring systems. Through numerical parameter studies we were able to describe the identified relationship between measuring quantities and material parameters quantitatively for two devices of this type. The evaluation method is based on the Bingham model. With this method it is possible to measure both the yield stress and the plastic viscosity of the fresh sample simultaneously. Device independence of the evaluation process is proven and an application to fiber-reinforced UHPC is presented.

scholarly journals Rheological Properties of Cement Pastes with Multiwalled Carbon Nanotubes

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Gintautas Skripkiunas ◽  
Ekaterina Karpova ◽  
Irmantas Barauskas ◽  
Joana Bendoraitiene ◽  
Grigory Yakovlev
Keyword(s):  
Carbon Nanotubes ◽  
Rheological Properties ◽  
Yield Stress ◽  
Multiwalled Carbon Nanotubes ◽  
High Performance ◽  
High Performance Concrete ◽  
Plastic Viscosity ◽  
Multiwalled Carbon ◽  
Cement Pastes ◽  
Rheological Test

The evaluation of rheological properties of cement systems is getting more relevant with growing interest to self-consolidating concrete (SCC), high-performance concrete (HPC) and ultrahigh-performance concrete (UHPC). The rheology models are a perspective tool to predict and manage the properties of cement systems in the fresh and hardened state. The current research is focused on the rheological test of cement systems modified by multiwalled carbon nanotubes (MWCNT) dispersion with and without polycarboxylate ether (PCE). The content of dispersion with 1% concentration of MWCNT in cement pastes varied from 0.125 to 0.5% by weight of cement. The dosage of PCE was taken as 0.6% by weight of cement. The cement pastes were prepared based on Portland cement without mineral additives. The rheological test was carried out at 5, 30, 60, and 120 min after mixing of cement paste. The rheological test established that modification of cement pastes by MWCNT dispersion in dosage 0.25% leads to the decrease of yield stress by 30.7% and increase of plastic viscosity by 29.6%. The combined modification by PCE and MWCNT dispersion shows the decrease in plastic viscosity of cement pastes by 9.90% in dosage of MWCNT equal to 0.5% by weight of cement, reduction of water demand by 20% for the same workability, and decrease of yield stress till 0 Pa. It gives the ability to obtain the self-compacting mixtures. The cement pastes with and without MWCNT dispersion revealed the shear-thinning behavior during 120 min after mixing. The modification of cement pastes by PCE with and without MWCNT dispersion showed the shear-thickening behavior which remains during 120 min after mixing.

Influence of Glass Powder on Rheological Properties of Ultra-High Performance Concrete Paste

2021 ◽  
Vol 1036 ◽  
pp. 419-431
Author(s):  
Xue Li Nan ◽  
Jian Rui Ji ◽  
Rong Yang Li ◽  
Yi Wang ◽  
Hao Chen ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Yield Stress ◽  
Silica Fume ◽  
High Performance ◽  
Glass Powder ◽  
High Performance Concrete ◽  
Shear Thickening ◽  
Plastic Viscosity ◽  
Ecological Problem ◽  
Ultra High Performance Concrete

Replacing cement and silica fume with glass powder to prepare ultra-high performance concrete (UHPC) is beneficial to solve the ecological problem in the field of civil engineering, but the technologies of preparation, transportation, pumping, and hardening of UHPC mainly relate to its rheological property. Therefore, this paper studied the influence of glass powder on the rheological properties of UHPC paste by performing the flow and the rheological test. Experimental results showed that when the cement and silica fume partially replaced by glass powder, the UHPC paste appears shear thickening, yield stress, plastic viscosity, and area of hysteresis loop decrease. This means that mixing glass powder can somehow inhibit the problems of segregation and bleeding of UHPC during pumping. In this manner, the dosage of the superplasticizer in UHPC is appropriately reduced, the filling capacity of UHPC during pouring is improved, and the energy required for UHPC in the pumping process is weakened. Compared with replacing cement, replacing silica fume with glass powder significantly increases the shear thickening and fluidity of UHPC paste, and at the same, reduces its yield stress and plastic viscosity. This indicates that the construction performance of UHPC is greatly improved with the replacement of silica fume. The fluidity and yield stress of UHPC paste satisfy the quadratic polynomial function relationship, and the replacement of cement and silica fume with glass powder should be less than 33% and 50%, respectively. Under this condition, the rheological properties of the UHPC paste are greatly improved and result in little negative impact on the mechanical properties of UHPC.

Development of Some Performance-Based Material Specifications for High-Performance Concrete Pavement

2003 ◽  
Vol 1834 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Prasada Rao Rangaraju
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Pavement ◽  
Performance Criteria ◽  
Test Results ◽  
Department Of Transportation ◽  
Performance Specifications ◽  
Concrete Materials ◽  
Practical Feasibility

In collaboration with FHWA, the Minnesota Department of Transportation (Mn/DOT) has successfully completed its first experimental high-performance concrete pavement (HPCP) project under the Testing and Evaluation Program (TE-30). This project is one of the 22 projects funded under the TE-30 Program. With a structural design life of 60 years, this HPCP is unique in that it incorporates significant changes to the existing Mn/DOT specifications on concrete materials. Some of the new materials-related specifications developed as a part of this project are based on performance criteria that influence long-term durability of the pavement structure. The background and considerations for selecting the new performance measures are discussed, and test results are presented that evaluate the practical feasibility of establishing and achieving the performance specifications.

The Fatigue Performance of High Performance Concrete Composite Girder

2019 ◽  
Author(s):  
C. Xu ◽  
B. Y. Zhang ◽  
Z. H. Hou
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Test Results ◽  
Normal Concrete ◽  
Bending Tests ◽  
Composite Girder ◽  
Tensile Performance ◽  
Negative Bending ◽  
The One ◽  
Push Out

<p>The application of high performance concrete has been increasingly concerned in the negative flexural region of steel‐concrete continuous composite girder because of its favorable tensile performance. However, the unclear cyclic and ultimate performance of a high performance concrete composite girder results to the problems which hinder the further application. In this case, a series of fatigue negative bending tests on HPC composite girders and fatigue push‐out tests on stud connectors in HPC were executed. The test results showed that the fatigue slip in the HPC composite girder was smaller than the normal concrete composite girder, and the fatigue life of stud in HPC was longer than the one in normal concrete. Meanwhile, according to the comparison between the stud fatigue live evaluations and test results, the AASHTO‐based evaluations were comparatively with larger safety redundancy, and JSCE was close to the test results but had smaller safety redundancy.</p>

scholarly journals On Flexural Performance of Girder-To-Girder Wet Joint for Lightweight Steel-UHPC Composite Bridge

2020 ◽  
Vol 10 (4) ◽  
pp. 1335 ◽  
Author(s):  
Shuwen Deng ◽  
Xudong Shao ◽  
Banfu Yan ◽  
Yan Wang ◽  
Huihui Li
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Bending Moment ◽  
Inhibitory Effect ◽  
Careful Consideration ◽  
Joint Interface ◽  
Test Results ◽  
Negative Moment ◽  
Composite Bridge ◽  
Negative Bending

Joints are always the focus of the precast structure for accelerated bridge construction. In this paper, a girder-to-girder joint suitable for steel-ultra-high-performance concrete (UHPC) lightweight composite bridge (LWCB) is proposed. Two flexural tests were conducted to verify the effectiveness of the proposed T-shaped girder-to-girder joint. The test results indicated that: (1) The T-shaped joint has a better cracking resistance than the traditional I-shaped joint; (2) The weak interfaces of the T-shaped joint are set in the areas with relatively lower negative bending moment, and thus the cracking risk could be decreased drastically; (3) The natural curing scheme for the joint is feasible, and the reinforcement has a very large inhibitory effect on the UHPC material shrinkage; The joint interface is the weak region of the LWCB, which requires careful consideration in future designs. Based on the experimental test results, the design and calculation methods for the deflection, crack width, and ultimate flexural capacity in the negative moment region of LWCB were presented.

The ability of high performance concrete to resist high temperature

2017 ◽  
Vol 8 (4) ◽  
pp. 392-401 ◽  
Author(s):  
Hassan A.M. Mhamoud ◽  
Jia Yanmin
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mass Loss ◽  
High Performance ◽  
Elevated Temperatures ◽  
High Performance Concrete ◽  
Sharp Decrease ◽  
Test Results ◽  
Content Type ◽  
Chinese Standard

Purpose This study aims to focus on the resistance to elevated temperatures of up to 700ºC of high-performance concrete (HPC) compared to ordinary Portland concrete (OPC) with regards to mass loss and residual compressive and flexural strength. Design/methodology/approach Two mixtures were developed to test. The first mixture, OPC, was used as the control, and the second mixture was HPC. After 28 days under water (per Chinese standard), the samples were tested for compressive strength and residual strength. Findings The test results showed that at elevated temperatures of up to 500ºC, each mixture experienced mass loss. Below this temperature, the strength and the mass loss did not differ greatly. Originality/value When adding a 10 per cent silica fume, 25 per cent fly, 25 per cent slag to HPC, the compressive strength increased by 17 per cent and enhanced the residual compressive strength. A sharp decrease was observed in the residual flexural strength of HPC when compared to OPC after exposure to temperatures of 700ºC.

Study on the Numerical Modeling of the SRHPC Frame

2010 ◽  
Vol 163-167 ◽  
pp. 1561-1564
Author(s):  
Pi Ji Hou ◽  
Shan Suo Zheng ◽  
Lei Li
Keyword(s):  
Finite Element ◽  
Numerical Modeling ◽  
High Performance ◽  
Applied Load ◽  
Mechanical Characteristics ◽  
High Performance Concrete ◽  
Frame Structure ◽  
Test Results ◽  
Modeling Methodology

The modeling methodology is investigated for steel reinforced high performance concrete (SRHPC) in this paper. According to the mechanical characteristics of the SRHPC members, the structural section can be divided into different zones, and the element suitable for each zone is determined. Some discussion is made for how to control finite element gridding as well as applied load. Hysteretic loops of the computation results and test results agree well with each other, indicating the accuracy and applicability of the methodology. This research may be helpful for the nonlinear finite analysis of the SRHPC frame structure.

Study on the Compressive Strength and Mixing of Ultra-High Performance Concrete

2013 ◽  
Vol 357-360 ◽  
pp. 825-828
Author(s):  
Su Li Feng ◽  
Peng Zhao
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Strength Properties ◽  
Test Method ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Ultra High Performance Concrete ◽  
Mixture Ratio

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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