Unit Cell Approach as a Multi Scale Modeling Technique for Predicting the Behaviour of Fiber Reinforced High Strength Concrete Under Compression

2011 ◽  
Author(s):  
Sunir Hassan ◽  
C. Lakshmana Rao ◽  
K. Ganesh Babu
Keyword(s):  
Compressive Strength ◽  
Volume Fraction ◽  
High Strength ◽  
Unit Cell ◽  
Fiber Reinforced ◽  
Material Behaviour ◽  
Strength Concrete ◽  
Volume Fractions ◽  
Coarse Aggregates ◽  
Fine Aggregates

Fiber reinforced concrete has been identified as a particulate composite consisting of hardened cement paste, fine aggregates, coarse aggregates, particulate fibers etc. and each constituent plays a significant role in the combined quasi brittle behaviour of the material. From the view point of a numerical modeler, a two phase model consisting of a matrix phase and a coarse aggregate phase is simple and sufficient enough to take care of the heterogeneity without affecting the capability of the model to predict the material behaviour as reported by Ghouse et al [1]. Thus the unit cell under consideration is modeled as a square with an inner circle (Fig. 1), the square representing the total volume fraction of combined properties of cement paste, fine aggregates, particulate fibers and water. The inner circle represents the total volume fraction of coarse aggregates in the material. This representative volume fraction is assigned with periodic boundary conditions to ensure uniformity in deformation and to avoid any discontinuities in the material once the unit cell has been repeatedly arranged to build up the macro sized material and has undergone deformation in elastic range. Ghouse et al [1] could identify only slight variations in the compressive strength of normal low strength concrete with varying aggregate volume fractions. A comparatively decreasing trend in compressive strength has also been observed initially when glass fiber reinforced high strength cement composite (GFRCC) was analyzed by Sunir et al [2]. Investigations proceed in the direction of predicting the material behaviour by replacing the glass fiber and its volume fraction with polypropylene fibers considered by Pavan [3] as being significant in improving the mechanical characteristics of the macro composite under consideration. An analysis of polymer fiber reinforced high strength concrete (PFRC) with similarly varying aggregate volume fractions could predict significantly decreasing trends in compressive strength for lower volume fractions. In future, the ease with which the unit cell approach predicts the behaviour of fiber reinforced plain mortar is also to be investigated in a similar manner.

Compressive Strength and Splitting Tensile Strength of Steel Fiber Reinforced Ultra High Strength Concrete (SFRC)

2010 ◽  
Vol 34-35 ◽  
pp. 1441-1444 ◽  
Author(s):  
Ju Zhang ◽  
Chang Wang Yan ◽  
Jin Qing Jia
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Splitting Tensile Strength ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Strength Concrete

This paper investigates the compressive strength and splitting tensile strength of ultra high strength concrete containing steel fiber. The steel fibers were added at the volume fractions of 0%, 0.5%, 0.75%, 1.0% and 1.5%. The compressive strength of the steel fiber reinforced ultra high strength concrete (SFRC) reached a maximum at 0.75% volume fraction, being a 15.5% improvement over the UHSC. The splitting tensile strength of the SFRC improved with increasing the volume fraction, achieving 91.9% improvements at 1.5% volume fraction. Strength models were established to predict the compressive and splitting tensile strengths of the SFRC. The models give predictions matching the measurements. Conclusions can be drawn that the marked brittleness with low tensile strength and strain capacities of ultra high strength concrete (UHSC) can be overcome by the addition of steel fibers.

Compressive Strength and Splitting Tensile Strength of Polyvinyl Alcohol Fiber Reinforced Ultra High Strength Concrete (PFRC)

2010 ◽  
Vol 150-151 ◽  
pp. 996-999
Author(s):  
Chang Wang Yan ◽  
Jin Qing Jia ◽  
Ju Zhang ◽  
Rui Jiang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Polyvinyl Alcohol ◽  
High Strength Concrete ◽  
Volume Fraction ◽  
High Strength ◽  
Splitting Tensile Strength ◽  
Fiber Reinforced ◽  
Strength Concrete ◽  
Strength Models

The marked brittleness with low tensile strength and strain capacities of ultra high strength concrete (UHSC) with compressive strength of 100 MPa can be overcome by the addition of polyvinyl alcohol (PVA) fibers. The compressive strength and splitting tensile strength of ultra high strength concrete containing PVA fibers are investigated this paper. The PVA fibers were added at the volume fractions of 0%, 0.17%, 0.25%, 0.34% and 0.5%. The compressive strength of the PVA fiber reinforced ultra high strength concrete (PFRC) reached a maximum at 0.5% volume fraction, being an 8.2% improvement over the UHSC. The splitting tensile strength of the PFRC improved with increasing the volume fraction, achieving 46.7% improvements at 0.5% volume fraction. The splitting strength models were established to predict the compressive and splitting tensile strengths of the PFRC. The models give predictions matching the measurements.

scholarly journals A Study on the Thermal Properties of High-Strength Concrete Containing CBA Fine Aggregates

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1493 ◽  
Author(s):  
In-Hwan Yang ◽  
Jihun Park
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Ultrasonic Velocity ◽  
High Strength Concrete ◽  
High Strength ◽  
Unit Weight ◽  
Test Results ◽  
Strength Concrete ◽  
Fine Aggregates

The thermal conductivity of concrete is a key factor for efficient energy consumption in concrete buildings because thermal conductivity plays a significant role in heat transfer through concrete walls. This study investigated the effects of replacing fine aggregates with coal bottom ash (CBA) and the influence of curing age on the thermal properties of high-strength concrete with a compressive strength exceeding 60 MPa. The different CBA aggregate contents included 25%, 50%, 75%, and 100%, and different curing ages included 28 and 56 days. For concrete containing CBA fine aggregate, the thermal and mechanical properties, including the unit weight, thermal conductivity, compressive strength, and ultrasonic velocity, were measured. The experimental results reveal that the unit weight and thermal conductivity of the CBA concrete were highly dependent on the CBA content. The unit weight, thermal conductivity, and compressive strength of the concrete decreased as the CBA content increased. Relationships between the thermal conductivity and the unit weight, thermal conductivity and compressive strength of the CBA concrete were proposed in the form of exponential functions. The equations proposed in this study provided predictions that were in good agreement with the test results. In addition, the test results show that there was an approximately linear relationship between the thermal conductivity and ultrasonic velocity of the CBA concrete.

J Integral of Steel Fiber Reinforced High Strength Concrete

2012 ◽  
Vol 476-478 ◽  
pp. 1568-1571
Author(s):  
Ting Yi Zhang ◽  
Guang He Zheng ◽  
Ping Wang ◽  
Kai Zhang ◽  
Huai Sen Cai
Keyword(s):  
High Strength Concrete ◽  
Fiber Volume Fraction ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Three Point Bending ◽  
Strength Concrete

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effects of influencing factors including water-cement ratio (W/C) and the fiber volume fraction (ρf) upon the critical value(JC) of J integral were studied. The results show that the variation tendencies of JC are different under different factors. JC meets the linear statistical relation with W/C, ρf, respectively.

Fracture Energy of Steel Fiber Reinforced High Strength Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 2230-2234
Author(s):  
Ting Yi Zhang ◽  
Zi Li Wang ◽  
Dan Ying Gao
Keyword(s):  
Fracture Energy ◽  
External Force ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
Volume Fraction ◽  
High Strength ◽  
Applied Force ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Strength Concrete

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC) and plain high strength concrete (HSC) with the size of 100 mm×100 mm×515 mm, the effects of influencing factors including the fiber volume fraction (ρf) and relative notch depth (a/W) upon the fracture energy and the work of applied force (gravity and external force) were studied. The results show that the effect of ρf upon the fracture energy is more obvious; the variation tendencies for the increment ratio of the fracture energy and that of the work of applied force are different under different factors; the fracture energy is dependent on the work of external force. Based on the test results, the formula was established for calculating the fracture energy.

scholarly journals The Benefits of Adding Corn Stalk Ash as a Substitution of Some Cement Against of Compressive Strength Concrete

2019 ◽  
Vol 4 (3) ◽  
pp. 208
Author(s):  
Sri Hartati Dewi ◽  
Roza Mildawati ◽  
Tio Perdana
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Silica Content ◽  
Corn Stalk ◽  
Strength Concrete ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Corn Plants ◽  
Construction Services

Concrete is a very important building material used in the world of construction services, and it is generally known that the good and bad properties of concrete can be seen from its compressive strength. Concrete consists of Portland Cement (PC) or other hydraulic cement, fine aggregates, coarse aggregates, and water, with or without using additional materials. Cement is one of the main mixtures of concrete constituents composed of natural resources such as lime (CaO), Silica (SiO₃), alumina (Al2O₃), little magnesia (MgO), and alkali. Silica is also found in corn. according to (Roesmarkam and Yuwono, 2002) corn plants have a Silica content of 20.6%. This study aims to determine the effect of utilization of corn stalk ash on compressive strength and modulus of elasticity of concrete. Cornstalk ash is used as a partial substitute for cement, with a mixture composition of 2%, 4%, 6%, 8%, and 10%. This study uses SNI 03-2834-2000 for mix design, with the added ingredient of 0.25% sikament NN. Cylindrical test specimen size (150 mm x 300 mm), the specimen was treated and tested at 28 days. Based on research using corn stalk ash 2%, 4%, 6%, 8%, and 10%. either without or using sikament NN the highest compressive strength at 8% is 20.8 Mpa and 20.4 Mpa, and decrease in usage of 10% corn stalk ash which is 18.2 Mpa and 18, 4 Mpa. The highest elastic modulus without or with sikament NN present in 8% ie 21656.14 Mpa and 21607.52 MPa. Modulus of Elasticity value decreased in the use of corn stalks 10% ash is 20366.28 Mpa and 20569.59 MPa. Based on the research, corn stalk ash can replace the role of part of cement in construction using corn stalk ash 8%.

Mechanical Properties of Modified Polypropylene Coarse Fiber-Reinforced, High-Strength, Lightweight Concrete

2011 ◽  
Vol 374-377 ◽  
pp. 1499-1506
Author(s):  
Rong Hui Zhang ◽  
Jian Li
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Lightweight Concrete ◽  
Volume Fraction ◽  
High Strength ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Fiber Volume

In this study, the effect of micro-expansion high strength grouting material (EGM) and Modified polypropylene coarse fiber (M-PP fiber) on the mechanical properties of lightweight concrete are investigated. The influence of EGM and M-PP fiber on compressive strength , flexural strength and drying shrinkage of concrete are researched, and flexural fracture toughness are calculated. Test results show that the effect of EGM and M-PP fiber volume fraction (Vf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly enhanced, and the rate of shrinkage is obviously decreased. It is observed that the shape of the descending branch of load-deflection and the ascending branch of shrinkage-age tends towards gently with the increase of Vf. And M-PP fiber reinforced lightweight aggregate concrete is more economical.

Effect of Stone Ash Mixture and Coconut Fiber on Concreate Compressive Strenght

2020 ◽  
Vol 6 (4) ◽  
pp. 462-471
Keyword(s):  
Compressive Strength ◽  
Laboratory Tests ◽  
Concrete Compressive Strength ◽  
Coconut Fiber ◽  
Normal Concrete ◽  
Strength Concrete ◽  
Coarse Aggregates ◽  
Concrete Mixtures ◽  
Fine Aggregates ◽  
Coconut Fibers

Abstract: The composition of the concrete mixture determines the compressive strength. Concrete mixtures generally consist of cement, water, coarse aggregates, fine aggregates, and concrete drugs. In this study, it will be tried to mix stone ash and coconut fibers. The purpose of this study is to find out the concrete compressive strength with add stone ash and coconut fibers to normal concrete. Data was collected through laboratory tests by carrying out an additional mixture of stone ash and coconut fibers. There were six types of specimens produced which were measured for 7, 14, 21, and 28 days. Variation of specimens 1) normal concrete, 2) normal concrete + stone ash, 3) normal concrete + coconut fiber (1.5%), 4) normal concrete + stone ash and coconut fiber (1.5%), 5) normal concrete + stone ash and 1% coconut fiber, 6) normal concrete + 1% coconut fiber. From the results of testing the concrete compressive strength was obtained 455 kg/cm2 for the age of concrete for 28 days with a mixture of normal concrete + stone ash.

scholarly journals Strength Properties of High-Strength Concrete Containing Coal Bottom Ash as a Replacement of Aggregates

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
In-Hwan Yang ◽  
Jihun Park ◽  
Nhien Dinh Le ◽  
Sanghwa Jung
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Bottom Ash ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Strength Properties ◽  
Pulse Velocity ◽  
Coal Bottom Ash ◽  
Strength Concrete ◽  
Fine Aggregates

Most previous studies on the strength properties of coal bottom ash (CBA) concrete have focused on concrete with a normal compressive strength, and thus, studies on the strength properties of high-strength concrete (HSC) containing CBA are limited. Therefore, the effects of replacing fine aggregates with CBA and variations in the curing age on the strength properties of HSC with a compressive strength of greater than 60 MPa were investigated in this study. The different CBA contents included 25, 50, 75, and 100%, and the different curing ages were 28 and 56 days. The mechanical properties of the HSC with CBA incorporated as fine aggregates were examined. The experimental results revealed that CBA could be partially or totally substituted for fine aggregates during HSC production. The test results also showed that the compressive, splitting tensile, and flexural strengths of the HSC containing CBA fine aggregates slightly decreased as the CBA content increased. Moreover, useful relationships between the compressive strength, splitting tensile strength, and flexural strength were suggested, and the predictions reasonably agreed with the measurements. Compared to those of the control specimen, the pulse velocities of the HSC specimens at various CBA contents decreased by less than 3%. In addition, equations for predicting the strength values of CBA concrete by using the ultrasonic pulse velocity were suggested.

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