scholarly journals Dynamic Properties Test and Constitutive Relation Study of Lightweight Aggregate Concrete under Uniaxial Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhiqing Zhao
Keyword(s):  
Elastic Modulus ◽  
Constitutive Model ◽  
Strain Rate ◽  
Dynamic Properties ◽  
Peak Stress ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Strain Rates ◽  
Aggregate Concrete ◽  
Ordinary Concrete

For the purpose of studying the dynamic properties of lightweight aggregate concrete, dynamic performance tests under uniaxial compression were conducted by considering 10 different strain rates ranging from 10−5/s to 10−1/s, from which the stress-strain curves under various compressive loads were obtained. From the stress-strain curves, parameters including peak stress, peak strain, and elastic modulus of lightweight aggregate concrete, as well as the concrete failure mode, were determined and examined. By reviewing the relevant literature on ordinary concrete, the dynamic properties of lightweight aggregate concrete were analyzed accordingly. Meanwhile, by applying the dynamic elastoplastic damage constitutive model, the effect of dynamic rate on lightweight aggregate concrete was calculated. The experimental results showed that the damage mode of lightweight aggregate concrete under the static and dynamic strain rates belonged to shear failure, which is different from that of ordinary concrete (binding material failure). On the other hand, it was also found that the peak stress and elastic modulus of lightweight aggregate concrete could be increased by 54.48% and 28.75%, respectively, with the increase of strain rate, suggesting that the loading strain rate has a stronger influence on lightweight aggregate concrete than on ordinary concrete. Based on the experimental data, both the peak stress and nondimensionalized elastic modulus are in linear relationship with the logarithm of the nondimensionalized strain rate. Moreover, the established constitutive model had been verified as an effective and reliable tool for simulating the dynamic rate effect of lightweight aggregate concrete.

scholarly journals Experimental Study on Dynamic Performance of Self-Compacting Lightweight Aggregate Concrete under Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Furong Li ◽  
Zhenpeng Yu ◽  
Yanli Hu
Keyword(s):  
Strain Rate ◽  
Dynamic Characteristics ◽  
Failure Modes ◽  
Dynamic Performance ◽  
Peak Stress ◽  
Lightweight Aggregate ◽  
The Self ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Ordinary Concrete

In order to study the dynamic characteristics of the self-compacting lightweight aggregate concrete (SCLC) under uniaxial compression, 10 different strain rates (10−5–10−1/s) were set up to examine the uniaxial compressive dynamic performance of ordinary concrete, lightweight aggregate concrete, and SCLC, respectively. The failure modes and stress-strain curves of the samples under different loading conditions were obtained through experiment. The dynamic characteristics of the SCLC were analyzed by comparing the failure modes and testing data under different loading conditions. The following conclusions are drawn: the failure modes of the SCLC belong to destruction of shale ceramsite, which are similar to that of the lightweight aggregate concrete. The peak stress and elastic modulus of the self-compacting lightweight aggregate gradually increase with the increase of the loading strain rate, but the extent of increase of the peak stress is lower than that of the ordinary concrete and lightweight aggregate concrete. Affected by the loading strain rate and the random coupling of concrete, the peak strain of the self-compacting lightweight aggregate shows a relatively discrete changing trend. At the same time, the compressive dynamic performance of the SCLC was analyzed from the perspective of failure mechanism with a quantitative point of view.

Constitutive Modeling for Elevated Temperature Flow Behavior of ZHMn34-2-2-1 Manganese Brass

2017 ◽  
Vol 872 ◽  
pp. 30-37
Author(s):  
Meng Han Wang ◽  
Kang Wei ◽  
Xiao Juan Li
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Flow Behavior ◽  
Peak Stress ◽  
Strain Rates ◽  
Hollomon Parameter ◽  
Prediction Ability ◽  
Absolute Relative Error ◽  
Deformation Behaviors ◽  
State Stress

The hot compressive deformation behaviors of ZHMn34-2-2-1 manganese brass are investigated on Thermecmastor-Z thermal simulator over wide processing domain of temperatures (923K-1073K) and strain rates (0.01s-1-10s-1). The true stress-strain curves exhibit a single peak stress, after which the stress monotonously decreases until a steady state stress occurs, indicating a typical dynamic recrystallization. A revised constitutive model coupling flow stress with strain, strain rate and deformation temperature is established with the material constants expressed by polynomial fitting of strain. Moreover, better prediction ability of the constitutive model is achieved by implementation of a simple approach for modified the Zener-Hollomon parameter considering the compensation of strain rate and temperature increment. By comparing the predicted and experimented values, the correlation coefficient and mean absolute relative error are 0.997 and 2.363%, respectively. The quantitative statistical results indicate that the proposed constitutive model can precisely characterize the hot deformation behavior of ZHMn34-2-2-1 manganese brass.

scholarly journals An Experimental Investigation of Dynamic Properties of Fiber-Reinforced Tire-Derived Lightweight-Aggregate Concrete

2020 ◽  
Vol 5 (6) ◽  
pp. 702-707
Author(s):  
Fariborz M. Tehrani ◽  
Nazmieh A. Masswadi ◽  
Nathan M. Miller ◽  
Arezoo Sadrinezhad
Keyword(s):  
Energy Absorption ◽  
Dynamic Properties ◽  
Fiber Reinforcement ◽  
Lightweight Aggregate ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Aggregate Concrete

This paper presents the results of an experimental study to investigate dynamic properties of polypropylene fiber-reinforced concrete beams with lightweight expanded shale (ES) and tire-derived aggregates (TDA). The mixture design followed past experiences in combining ES and TDA to enhance toughness and energy absorption in flexural behavior. The new mixture also contained 2% fiber by volume to improve such properties further. Experiments included compressive testing on cylindrical specimens as well as flexural testing on rectangular specimens to verify mechanical properties of fiber-reinforced tire-derived lightweight aggregate concrete (FRTDLWAC) subject to static loading. The results of these experiments confirmed reduction of mechanical strength due to addition of TDA and improvements in flexural strength due to fiber reinforcement. The dynamic testing included non-destructive impact loads applied to flexural specimens using a standard Schmidt hammer. A high-speed camera recorded the response of the system at 200 frames per second to allow detailed observations and measurements. Interpretation of energy-based dynamic results revealed that TDA enhances energy absorption through damping in flexural behavior. Results also indicated that fiber reinforcement reduces the amount of absorbed dynamic energy, even though; it enhances the absorbed strain energy due to crack bridging effect.

Experimental Study of Stress-Strain Curves of Lightweight Aggregate Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1762-1767 ◽  
Author(s):  
Xiang Liu ◽  
Jiang Tao Kong
Keyword(s):  
Strain Curve ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Concrete Material ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Strength Grade ◽  
Strain Relationship

According to the contrast test of LC30, LC40 lightweight aggregate concrete and C30, C40 common concrete , the text researched the mechanical property of lightweight aggregate concrete and ordinary concrete in the same strength grade and obtained the regularity of stress-strain curve of lightweight aggregate concrete in different strength grade. Then we contrasted the experimental results and planning model, analysed the difference, and suggested that the standards should improve the descent stage of the stress-strain curve of lightweight aggregate concrete combined with correlative experiments data, and give the equation of the descent stage of stress-strain curves. Concrete material in axial compression is the basic physical mechanical performance of concrete material, and is the main basis for researching bearing capacity and deformation of concrete construction. The stress-strain relationship is all-around macroscopic reaction of basal compressive property . There have been many experiments work about the stress-strain relationship of lightweight aggregate concrete at home and abroad , and found the peak strain of lightweight aggregate concrete is higher than that of ordinary concrete in the context of same peak stress .In this paper, on the basis of experimental investigations of lightweight aggregate concrete , aim at the stress-strain relationship ,we have take comparison experiment about LC30,LC40 lightweight aggregate concrete and C30,C40 ordinary concrete , and sort out stress-strain curve under the condition of the shaft center being compressed, so get the average tress-strain curve of LC30,LC40 lightweight aggregate concrete , and analyse the curve.

Experimental Study on Bond Behavior of Profiled Steel Sheet-Lightweight Aggregate Concrete Composite Slab

2012 ◽  
Vol 594-597 ◽  
pp. 721-724
Author(s):  
Yan Kun Zhang ◽  
Yan Xiao Han ◽  
Ze Zao Song
Keyword(s):  
Experimental Study ◽  
Steel Sheet ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Composite Slab ◽  
Bond Behavior ◽  
Ordinary Concrete ◽  
Relationship Of ◽  
The Relationship

At present, there are much more researches on the ordinary concrete composite slab, and that on the lightweight aggregate concrete composite slab are relatively less. In this paper, the shear-bond behavior of lightweight aggregate concrete composite slab, with the profiled steel sheet YX-76-344-688, which is commonly used in China is studied. Base on experiments, the cracks developing process and its regularities of distribution, the bonding and slipping between profiled sheeting and concrete, the relationship of load and mid-span deflection, ultimate bearing capacity etc. are studied.

Mesoscopic finite element analysis on dynamic direct tensile failure of lightweight aggregate concrete and corresponding size effect

2021 ◽  
pp. 105678952110441
Author(s):  
Wenxuan Yu ◽  
Liu Jin ◽  
Xi Liu ◽  
Xiuli Du
Keyword(s):  
Tensile Strength ◽  
Size Effect ◽  
Strain Rate ◽  
Lightweight Aggregate ◽  
Tensile Failure ◽  
Lightweight Aggregate Concrete ◽  
Element Analysis ◽  
Aggregate Concrete ◽  
Direct Tensile ◽  
Direct Tensile Strength

A comprehensive finite element analysis at the mesoscopic level has been conducted into the complex topic of size effect coupling dynamic strain-rates. Taking the lightweight aggregate concrete (LWAC) dumbbell-shaped samples as the object of numerical investigation, the influence of strain-rate (with the range of 10−5/s ∼ 100/s) on direct-tensile failure of LWAC (including different lightweight aggregate volume fractions [Formula: see text] = 40%, 30% and 20%) was discussed. Subsequently, the structure size of LWAC samples was further expanded (width W = 100, 200 and 300 mm) and the dynamic size effect on direct-tensile strength was investigated. Numerical results show that both the direct-tensile strength and its corresponding size effect of LWAC exhibit a strain-rate dependent behaviour. The increasing strain-rate can gradually weaken the size effect of LWAC and direct-tensile strength would be independent to the structure size as the strain-rate reaches the critical strain-rate. The increasing lightweight aggregate volume fraction can reduce direct-tensile strength. Furthermore, a dynamic size effect model establishing the direct link between the strain-rate effect and size effect was proposed, which can quantitatively predict the dynamic direct-tensile strength of LWAC.

scholarly journals A methodology to obtain an analytical formula for the elastic modulus of lightweight aggregate concrete

DYNA ◽  
2015 ◽  
Vol 82 (193) ◽  
pp. 98-103
Author(s):  
Flávio de Souza-Barbosa ◽  
Michèle Cristina Resende-Farage ◽  
Aldemon Lage-Bonifácio ◽  
Anne Lise Beaucour ◽  
Sophie Ortola
Keyword(s):  
Elastic Modulus ◽  
Curve Fitting ◽  
Analytical Formula ◽  
Lightweight Aggregate ◽  
Experimental Results ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Good Agreement

This work proposes a methodology to predict the elastic modulus of lightweight aggregate concretes. To this end an analytical formula is achieved by curve fitting experimental results from 135 concrete samples made of 45 different mixes. The validation of the proposed methodology is carried out by applying the obtained analytical formula to a set of 90 concrete samples made of 30 different mixes. Comparisons with other methods applied to predicting the elastic modulus of lightweight aggregate concretes indicate that the results show good agreement and suggest that the proposed methodology could be applied in practical situations.

scholarly journals Deformation Analysis of Reinforced Beams Made of Lightweight Aggregate Concrete

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 20 ◽  
Author(s):  
Darius Bacinskas ◽  
Deividas Rumsys ◽  
Aleksandr Sokolov ◽  
Gintaris Kaklauskas
Keyword(s):  
Numerical Analysis ◽  
Constitutive Model ◽  
Lightweight Concrete ◽  
Numerical Algorithms ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Deformation Analysis ◽  
Engineering Practice ◽  
Aggregate Concrete ◽  
Concrete Elements

In the present trend of constructing taller and longer structures, the application of lightweight aggregate concrete is becoming an increasingly important advanced solution in the modern construction industry. In engineering practice, the analysis of lightweight concrete elements is performed using the same algorithms that are applied for normal concrete elements. As an alternative to traditional engineering methods, nonlinear numerical algorithms based on constitutive material models may be used. The paper presents a comparative analysis of curvature calculations for flexural lightweight concrete elements, incorporating analytical code methods EN 1992-1 and ACI 318-19, as well as a numerical analysis using the constitutive model of cracked tensile lightweight concrete recently proposed by the authors. To evaluate the adequacy of the theoretical predictions, experimental data of 51 lightweight concrete beams of five different programs reported in the literature were collected. A comparison of theoretical and experimental results showed that the most accurate predictions are obtained using numerical analysis and the constitutive model proposed by the authors. In the future, the latter algorithm can be used as a reliable tool for improving the design standard methods or numerical modeling of lightweight concrete elements subjected to short-term loading.

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