scholarly journals Dynamic Constitutive Model for Reactive Powder Concrete with Standard Curing

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Steel Fiber ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Strengthening Effect ◽  
Compression Tests ◽  
Softening Effect ◽  
Impact Compression ◽  
Reactive Powder

In view of the disadvantages of steam curing of reactive powder concrete (RPC), RPC with standard curing (SCRPC) is proposed. SC-RPC is an ultra-high strength concrete material prepared with high strength cement, silica fume, and gypsum by standard curing. In this study, quasi-static and impact compression tests were performed to investigate the mechanical properties of SC-RPC. The results show that steel fiber and the strain rate significantly affect the compression performance. Nevertheless, the Holmquist–Johnson–Cook (HJC) constitutive model is mainly used to analyze the dynamic response of brittle materials, such as common concrete, under shock and impact. Therefore, based on the quasi-staticand impact compression tests and the HJC constitutive model for concrete, by analyzing the steel fiber strengthening effect under quasi-static uniaxial compression, strain rate hardening, and the damage softening effect under SHPB impact compression, the steel fiber strengthening factor Kf , dynamic increase factor DIF, and revised damage variable D are introduced, and a modified HJC constitutive model for RPC with standard curing is proposed.

scholarly journals Compressive Properties and Constitutive Model of Semicrystalline Polyethylene

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2895
Author(s):  
Kebin Zhang ◽  
Wenbin Li ◽  
Yu Zheng ◽  
Wenjin Yao ◽  
Changfang Zhao
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Yield Stress ◽  
Dynamic Compression ◽  
Molecular Structures ◽  
Strengthening Effect ◽  
Compression Tests ◽  
Compression Process ◽  
Softening Effect ◽  
Constitutive Parameters

The mechanical properties of polyethylene (PE) materials are greatly influenced by their molecular structures, environmental temperature, and strain rate. In this study, static and dynamic compression tests were performed on two semicrystalline PE materials—ultrahigh molecular weight polyethylene (UHMWPE) and high-density polyethylene (HDPE). The stress–strain curves of HDPE and UHMWPE under uniaxial compression at temperatures of −40–120 °C and strain rates of 0.001–5500 s−1 were obtained. The research findings suggest that both the UHMWPE and HDPE showed significant strain rate-strengthening effect and temperature-softening effect. In particular, HDPE exhibited better compression resistance and high-temperature resistance. The relationships between the yield stress and temperature and between the yield stress and strain rate for both materials were fitted, and the Cowper–Symonds constitutive model was built while considering the temperature effect. The parameters of the constitutive model were obtained and input into LS-DYNA software to simulate the dynamic compression process of HDPE. The simulation result was consistent with the test result, validating the accuracy of the constitutive parameters.

scholarly journals Properties of Reactive Powder Concrete Using Local Materials and Various Curing Conditions

2019 ◽  
Vol 4 (6) ◽  
pp. 74-83 ◽  
Author(s):  
Gamal I. K. ◽  
K. M. Elsayed ◽  
Mohamed Hussein Makhlouf ◽  
M. Alaa
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Hot Water ◽  
Reactive Powder Concrete ◽  
Normal Water ◽  
Reactive Powder ◽  
Local Materials

Reactive Powder Concrete RPC is comprise of (cement, quartz powder, sand, and superplasticizer) mixture with low water/cement ratio. It has not coarse aggregates and characterized by highly dense matrix, high strength concrete, excellent durability, and economic. This study aims to investigate fresh and hardened properties of locally cast RPC with several available economical materials such as silica fume (SF), fly ash (FA), steel fiber (STF), and glass fiber (GF). Experimental investigation were performed to study the effectiveness of partial replacement of cement by SF or FA to reach ultra-high strength concrete, effect of additional materials STF or GF in order to improve the fracture properties of the RPC mixes, and influence of the treated with normal water as well as with hot water. Fifteen different RPC mixes were cast with 20, 25, 30, and 35% cement replacement by SF, 25% cement replacement by FA, and another proportions taken combination between SF and FA with percentages 15, 20, 25% FA and constant 10% SF. Varying fiber types (steel fiber or glass fiber) added to concrete by different percentages 1, 2, and 3%. Specimens were treated with normal water 25ᵒC and hot water at 60ᵒC and 90ᵒC by 2 mixes with silica fume content 25% of binder and steel fiber content 2% by total volume. Performance of the various mixes is tested by the slump flow, compressive strength, flexure strength, splitting tensile strength, and density. The production of RPC using local materials is successfully get compressive strength of 121 MPa at the age of 28 days at standard conditions and normal water curing 25°C with Silica fume content 25% of binder and steel fiber content 2% by total volume of RPC and water/binder ratio of 0.25.  The results also showed the effect of curing by hot water 60 and 90°C, it is observed that compressive strength increases proportionally with curing temperatures and a compressive strength of 149.1 MPa at 90°C for 1days was obtained.

scholarly journals Investigation of the Match Relation between Steel Fiber and High-Strength Concrete Matrix in Reactive Powder Concrete

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1751 ◽  
Author(s):  
Guangyao Yang ◽  
Jiangxiong Wei ◽  
Qijun Yu ◽  
Haoliang Huang ◽  
Fangxian Li
Keyword(s):  
Compressive Strength ◽  
Steel Fiber ◽  
High Strength ◽  
Steel Fibers ◽  
Peak Strength ◽  
Reactive Powder Concrete ◽  
Medium Length ◽  
Reactive Powder ◽  
Concrete Matrix ◽  
Strength And Toughness

This study investigated the strength and toughness of reactive powder concrete (RPC) made with various steel fiber lengths and concrete strengths. The results indicated that among RPC samples with strength of 150 MPa, RPC reinforced with long steel fibers had the highest compressive strength, peak strength, and toughness. Among the RPC samples with strength of 270 MPa, RPC reinforced with short steel fibers had the highest compressive strength, and peak strength, while RPC reinforced with medium-length steel fibers had the highest toughness. As a result of the higher bond adhesion between fibers and ultra-high-strength RPC matrix, long steel fibers were more effective for the reinforcement of RPC with strength of 150 MPa, while short steel fibers were more effective for the reinforcement of RPC with strength of 270 MPa.

Impact Experimental Study for Dynamic Character of Reactive Powder Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 187-191
Author(s):  
Wan Peng Wang ◽  
Yong Le Hu ◽  
Xin Tao Ren ◽  
Yi Bo Xiong ◽  
Kang Zhao ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Failure Strain ◽  
Test System ◽  
Experimental Result ◽  
Reactive Powder Concrete ◽  
Strain Rates ◽  
Dynamic Tensile Strength ◽  
Impact Compression ◽  
Reactive Powder

In order to systematically study dynamic mechanics character of reactive powder concrete (RPC), impact compression experiments and impact flattened Brazilian disc specimens of RPC have been investigated with modified split Hopkinson pressure bar (SHPB) experimental facility using brass pulse shaper, curves about stress versus strain and other parameters at strain rates of 20.3/s~137.0/s were obtained from impact compression. The dynamic tensile strength and tensile failure strain at strain rates of 3.4/s~26.2/s were obtained from impact flattened Brazilian. For comparison, the quasi-static compress and split tension of RPC were obtained with an MTS 810 materials test system and CSS-88500 electron universal material testing machine.The experimental result show that dynamic compression strength , elastic modulus and failure strain,dynamic tensile strength and failure strain significantly increase comparing to quasi-static experiment, RPC have the character of impact harding and ductility enhancement. RPC exhibit excellent failure patterns at high strain rate. Whether impact compression or impact splitting under strain rate including this paper ’s experiments, the relationship between the DIFC or DIFT and the logarithm of strain rateis linear.

scholarly journals Shear Strength of Steel Fiber Reinforced Reactive Powder Concrete & Geopolymer Concrete – A Comparison

2021 ◽  
Author(s):  
Aravind S Kumar ◽  
Bharati Raj J ◽  
Keerthy M Simon
Keyword(s):  
Shear Strength ◽  
Steel Fiber ◽  
Load Capacity ◽  
High Strength ◽  
Steel Fibers ◽  
Reactive Powder Concrete ◽  
Polymer Concrete ◽  
Geopolymer Concrete ◽  
Fiber Reinforced ◽  
Reactive Powder

Reactive Powder Concrete (RPC) is an ultra-high strength concrete composite prepared by the replacement of natural aggregates with quartz powder, silica fume and steel fibers. The use of RPC yields high strength, high ductile concrete with optimized material use and contributes to economic, sustainable and ecofriendly constructions. Past research has indicated that RPC offers significant improvement in the mechanical and physical properties owing to its homogenous composition with less defects of voids and microcracks. This leads to enhancement of ultimate load capacity of RPC members and results in superior ductility, energy absorption, tensile strain-hardening behavior, crack control capability and durability. Geo-polymer concrete (GPC) is a type of concrete that is made by reacting aluminate and silicate bearing materials with a caustic activator. Usually, waste materials such as fly ash or slag from iron and metal production are used, which helps lead to a cleaner environment. This paper attempts to review the effect of steel fibers on the shear strength of steel fiber reinforced RPC and compare the results with those of geopolymer concrete.

scholarly journals Stractural Behavior of Reinforced Concrete Corbel Using High-Strength Materials under Monotonic and Repeated Loads

2019 ◽  
Vol 2 (2) ◽  
pp. p1
Author(s):  
Al-Talqany F. J. ◽  
Alhussainy A. M.
Keyword(s):  
Steel Fiber ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Ultimate Shear Strength ◽  
Variable Parameters ◽  
Repeated Load ◽  
Concrete Materials ◽  
Precast Structures ◽  
Reactive Powder ◽  
Monotonic Load

The growth of Development techniques for high strength materials and precast structures leads to increase the interesting on these technics. This study will focus on the corbels which made from high strength materials (Reactive Powder Concrete materials) which including  the testing of (15 samples) and their cost, twelve of them were testing under a vertical monotonic load, while the other sample putted under the effect of repeated load. As well as, the samples divided to various groups according to many variable parameters which are (ratio of steel fiber, (a/d) ratio, existing the secondary stirrups steel, type of loading). Thus, these parameters effected on the ultimate shear strength, first crack loading, ultimate deflection, load-deflection curves, ductility and stiffness.

Static Properties of Plain Reactive Powder Concrete Beams

2006 ◽  
Vol 302-303 ◽  
pp. 521-527 ◽  
Author(s):  
Ri Gao ◽  
Zhi Min Liu ◽  
Li Qian Zhang ◽  
Piet Stroeven
Keyword(s):  
Mechanical Properties ◽  
Crack Extension ◽  
Steel Fiber ◽  
Concrete Beams ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Static Properties ◽  
Simply Supported ◽  
Reactive Powder ◽  
Strength And Durability

Reactive powder concrete (RPC) is a new kind of ultra-high strength and upper ductility concrete first developed in 1990’s in France. In this paper, the RPC mixture proportion is optimized and its mechanical properties, such as compressive strength, flexural strength, elastic modulus, and its durability, are tested and discussed. Based on the optimal mixture proportion, four simply supported plain RPC beams (without reinforcement bars) are made and tested. The mechanical properties of plain RPC beams, including section deformation, load-displacement relationship, failure forms, crack distribution, crack extension, and ultimate flexural capacity, are discussed. It is concluded that RPC is an excellent material with high strength and durability. Steel fiber is important both to control the crack extension and to enhance the ductility of RPC beams.

scholarly journals Investigation on Damage Characteristic and Constitutive Model of Deep Sandstone under Coupled High Temperature and Impact Loads

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhang Rongrong ◽  
Yang Yi ◽  
Ma Dongdong
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Strain Rate ◽  
Test Data ◽  
Impact Load ◽  
High Temperature Treatment ◽  
Strengthening Effect ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Damage Constitutive Model

To investigate the coupling damage characteristics of rock after high-temperature treatment under impact load, dynamic uniaxial compression tests for deep sandstone specimen under laboratory conditions varying with high temperature (i.e., 25°C, 100°C, 300°C, 500°C, 700°C, and 900°C) and strain rate (i.e., 170 s-1, 205 s-1, and 240 s-1) were performed using splitting Hopkinson pressure bar (SHPB) system. Coupling damage variable of deep sandstone was deduced based on the Lemaitre equivalent strain theory. Moreover, the damage parameters of deep sandstone were systematically determined according to the test data, and the effects of high temperature and strain rate on damage growth curves were investigated. Finally, a dynamic compound damage constitutive model, which could consider the coupling damage, was established and verified to describe the dynamic mechanical characteristic of deep sandstone. Theoretical and experimental results indicated that the simulated stress-strain curves matched the test data well and the proposed coupling damage constitutive model could reflect the high temperature-induced weakening and strain rate strengthening effect.

Tests on Mechanical Properties and Anti-Explosion Performance of Steel-Fiber Reactive Powder Concrete

2011 ◽  
Vol 368-373 ◽  
pp. 436-440
Author(s):  
Chun Ming Song ◽  
Ming Yang Wang ◽  
De Rong Wang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Shear Strength ◽  
Steel Fiber ◽  
High Strength ◽  
Reactive Powder Concrete ◽  
Compression Coefficient ◽  
Reactive Powder ◽  
Very High

In order to get mechanical properties and anti-explosion capability parameters, some RPC samples with 5% steel fiber are tested, many groups data were obtained such as compressive strength, shear strength and fracture toughness. The model tests are also carried out on RPC shelter plate under contact explosion, the most important parameter to express anti-explosion capability,i.e. compression coefficient of the material, is obtained by above experiments and theory study, the results of tests show RPC with steel fiber has very high strength and anti-explosion capability, its compressive strength and anti-explosion capability are about six and three times higher than those of C30 concrete respectively.

scholarly journals Compressive Behavior and Mechanical Characteristics and Their Application to Stress-Strain Relationship of Steel Fiber-Reinforced Reactive Powder Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Baek-Il Bae ◽  
Hyun-Ki Choi ◽  
Bong-Seop Lee ◽  
Chang-Hoon Bang
Keyword(s):  
Mechanical Properties ◽  
High Strength Concrete ◽  
Steel Fiber ◽  
High Strength ◽  
Steel Fibers ◽  
Reactive Powder Concrete ◽  
Test Results ◽  
Strength Concrete ◽  
Estimation Equations ◽  
Reactive Powder

Although mechanical properties of concrete under uniaxial compression are important to design concrete structure, current design codes or other empirical equations have clear limitation on the prediction of mechanical properties. Various types of fiber-reinforced reactive powder concrete matrix were tested for making more usable and accurate estimation equations for mechanical properties for ultra high strength concrete. Investigated matrix has compressive strength ranged from 30 MPa to 200 MPa. Ultra high strength concrete was made by means of reactive powder concrete. Preventing brittle failure of this type of matrix, steel fibers were used. The volume fraction of steel fiber ranged from 0 to 2%. From the test results, steel fibers significantly increase the ductility, strength and stiffness of ultra high strength matrix. They are quantified with previously conducted researches about material properties of concrete under uniaxial loading. Applicability of estimation equations for mechanical properties of concrete was evaluated with test results of this study. From the evaluation, regression analysis was carried out, and new estimation equations were proposed. And these proposed equations were applied into stress-strain relation which was developed by previous research. Ascending part, which was affected by proposed equations of this study directly, well fitted into experimental results.

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