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.

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

2019 ◽  
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 increasing important advanced solution in the modern construction industry. In engineering practice, the analysis of lightweight concrete elements is performed using the same algorithms used 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 318-14, 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 tested during five different programmes 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 modelling of lightweight concrete elements subjected to short-term loading.

scholarly journals Numerical Deformation Analysis of Reinforced Lightweight Aggregate Concrete Flexural Members

2021 ◽  
Author(s):  
Darius Bacinskas ◽  
Deividas Rumsys ◽  
Gintaris Kaklauskas
Keyword(s):  
Reinforced Concrete ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Full Scale ◽  
Lightweight Aggregate Concrete ◽  
Deformation Analysis ◽  
Aggregate Concrete ◽  
Flexural Members ◽  
Finite Element Software ◽  
Concrete Elements

In the modern construction industry, lightweight aggregate concrete (LWAC) is often used in the production of load-bearing structural members. LWAC can be up to 40% lighter by volume in comparison to normal strength concrete. On the other hand, the lack of adequate numerical models often limits the practical application of innovative building materials, such as lightweight concrete, in real projects. This trend is due to the uncertainties in design standard methods and calculation errors, the level of which is generally unacceptable to civil engineers in terms of safety and reliability. In the present paper, a comparative numerical deformation analysis of a full-scale bridge deck slab and girder has been carried out. Using the physical model proposed by the authors and the finite element software ATENA, the deformations of full–scale lightweight and traditional reinforced concrete elements under short-term effects of permanent and variable loads was compared. Depending on the safety and serviceability limit requirements, it was found that the amount of longitudinal reinforcement in lightweight reinforced concrete elements can be reduced compared to normal reinforced concrete elements with the same parameters. The results of the numerical analysis show that the deformation analysis model proposed by the authors can be a reliable tool for the design of lightweight concrete flexural members by selecting the optimum geometrical and reinforcement parameters limited by the stiffness condition.

Permeability of Lightweight Aggregate Concrete with Mineral Admixture

2013 ◽  
Vol 857 ◽  
pp. 105-109
Author(s):  
Xiu Hua Zheng ◽  
Shu Jie Song ◽  
Yong Quan Zhang
Keyword(s):  
Pore Structure ◽  
Lightweight Concrete ◽  
Chloride Ion ◽  
Lightweight Aggregate ◽  
Total Porosity ◽  
Normal Weight ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete

This paper presents an experimental study on the permeability and the pore structure of lightweight concrete with fly ash, zeolite powder, or silica fume, in comparison to that of normal weight aggregate concrete. The results showed that the mineral admixtures can improve the anti-permeability performance of lightweight aggregate concrete, and mixed with compound mineral admixtures further more. The resistance to chloride-ion permeability of light weight concrete was higher than that of At the same strength grade, the anti-permeability performance of lightweight aggregate concrete is better than that of normal weight aggregate concrete. The anti-permeability performance of LC40 was similar to that of C60. Mineral admixtures can obviously improve the pore structure of lightweight aggregate concrete, the total porosity reduced while the pore size decreased.

Lightweight Aggregate Concrete as an Alternative for Dense Concrete in Post-Tensioned Concrete Slab

2018 ◽  
Vol 926 ◽  
pp. 140-145 ◽  
Author(s):  
Małgorzata Mieszczak ◽  
Lucyna Domagała
Keyword(s):  
Mechanical Properties ◽  
Lightweight Concrete ◽  
Concrete Slab ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Large Span ◽  
Shrinkage And Creep ◽  
Theoretical Results ◽  
Post Tensioned

The paper presents the results of tests conducted on two lightweight aggregate concretes made of new national Certyd artificial aggregate. This research is intended to first application of lightweight concrete to construct large-span post-tensioned slab. In addition to mechanical properties development, shrinkage and creep during 3 months of loading were tested. The obtained results are compared with theoretical results predicted by standard. Conducted tests indicated, that measured values of shrinkage and creep are significantly lower than predicted ones. This is promise for application of tested concrete in construction of post-tensioned slabs.

Evaluation of fire performance of lightweight concrete wall panels using finite element analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Irindu Upasiri ◽  
Chaminda Konthesingha ◽  
Anura Nanayakkara ◽  
Keerthan Poologanathan ◽  
Brabha Nagaratnam ◽  
...  
Keyword(s):  
Finite Element ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Fire Performance ◽  
Concrete Wall ◽  
Aggregate Concrete ◽  
Content Type ◽  
Wall Panels ◽  
Foamed Concrete

Purpose In this study, the insulation fire ratings of lightweight foamed concrete, autoclaved aerated concrete and lightweight aggregate concrete were investigated using finite element modelling. Design/methodology/approach Lightweight aggregate concrete containing various aggregate types, i.e. expanded slag, pumice, expanded clay and expanded shale were studied under standard fire and hydro–carbon fire situations using validated finite element models. Results were used to derive empirical equations for determining the insulation fire ratings of lightweight concrete wall panels. Findings It was observed that autoclaved aerated concrete and foamed lightweight concrete have better insulation fire ratings compared with lightweight aggregate concrete. Depending on the insulation fire rating requirement of 15%–30% of material saving could be achieved when lightweight aggregate concrete wall panels are replaced with the autoclaved aerated or foamed concrete wall panels. Lightweight aggregate concrete fire performance depends on the type of lightweight aggregate. Lightweight concrete with pumice aggregate showed better fire performance among the normal lightweight aggregate concretes. Material saving of 9%–14% could be obtained when pumice aggregate is used as the lightweight aggregate material. Hydrocarbon fire has shown aggressive effect during the first two hours of fire exposure; hence, wall panels with lesser thickness were adversely affected. Originality/value Finding of this study could be used to determine the optimum lightweight concrete wall type and the optimum thickness requirement of the wall panels for a required application.

Effect of confinement on the behaviour of high-strength lightweight concrete columns

1986 ◽  
Vol 13 (6) ◽  
pp. 741-751 ◽  
Author(s):  
R. Basset ◽  
S. M. Uzumeri
Keyword(s):  
Experimental Investigation ◽  
Lightweight Concrete ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Concrete Columns ◽  
Lightweight Aggregate Concrete ◽  
Test Results ◽  
Aggregate Concrete ◽  
Concrete Confinement

This paper summarizes an experimental investigation into the behaviour of high strength sand – lightweight concrete columns confined with rectangular ties. Fifteen reinforced and three unreinforced specimens were tested under monotonically increasing axial compression. Variables considered in this study were the longitudinal steel distribution and tie configuration, the tie steel spacing, the amount of tie steel, and the amount of longitudinal steel.The results indicated that unconfined high-strength lightweight aggregate concrete is a brittle material. The addition of lateral confining steel significantly improved the behaviour of this material, with a large amount of lateral steel resulting in very ductile behaviour. The tie configuration and resulting distribution of longitudinal steel contributed significantly to the confinement of concrete, with well-distributed steel resulting in improved behaviour. The ratio of specimen to cylinder concrete strength was observed to be 0.98, which is much higher than the commonly assumed value of 0.85.The test results were compared with results from selected theoretical confinement models. Based on the results of this investigation, existing models for concrete confinement give unconservative results for high-strength lightweight aggregate concrete and overestimate the ductility that can be achieved with this material. Key words: columns, confinement, ductility, high-strength concretes, lightweight aggregate concretes, reinforcement, stress–strain relationships, tests, ties, toughness.

Influence of the Steel Fiber Length on the Properties of Lightweight Concrete

2013 ◽  
Vol 739 ◽  
pp. 251-254
Author(s):  
Ru Jie Huang ◽  
Chen Shi ◽  
Guo Xin Li
Keyword(s):  
Tensile Strength ◽  
Fiber Length ◽  
Elasticity Modulus ◽  
Steel Fiber ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Earthquake Resistance ◽  
Lightweight Aggregate Concrete ◽  
Light Weight ◽  
Aggregate Concrete

Lightweight aggregate concrete has lower density and lower elasticity modulus, so it has better earthquake resistance. But the low strength limited the application of lightweight concrete. Steel fiber can improve the strength of lightweight aggregate concrete. In this paper, the influences of different lengths of steel fiber on the slump, compressive strength, splitting tensile strength and antiflex cracking strength are investigated. The results show that adding steel fiber reduces the workability of the concrete mixture, but it improved the each strength of light weight concrete and different lengths have the different regularity of effects.

Surface Modification for Porous Artificial Lightweight Aggregate and Mechanical Properties of the Resulting Concrete

2011 ◽  
Vol 117-119 ◽  
pp. 1302-1305
Author(s):  
Ning Liao ◽  
Hong Zhi Cui
Keyword(s):  
Mechanical Properties ◽  
Surface Modification ◽  
Water Absorption ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
High Water ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
High Water Absorption ◽  
Change Material

This research is one part of preliminary work for integrated structural-functional energy storage concrete by using porous artificial lightweight aggregate and phase change material. Lightweight aggregate concrete (LWAC) has been applied more and more extensively in recent years, but high water absorption of porous artificial lightweight aggregate (LWA) is inconvenient for LWAC production. In order to improve LWA application, in this paper, two aspects of lightweight aggregate (LWA) study have been carried out, namely, a) LWA surface modification. The effects of different concentration of surface modifier on water absorption of modified LWA were studied. b) Mechanical properties of lightweight aggregate concrete made of the unmodified and modified LWAs Through comparing the water absorption of unmodified and modified LWAs, it can be known that the surface modification for LWA can reduce the water absorption obviously. The three kinds of lightweight concrete possess nearly same strength at 7-day and, at 28-day, the strength of LWAC using 1:20 modified LWA is highest and that of LWAC using 1:5 modified LWA is lowest. 28 days compressive strength of LWAC using 1:20 modified LWA could be up to 46.1MPa.

scholarly journals Novel Core-Shell Non-Sintered Lightweight Aggregate Concrete for Better Properties in Wallboard

2021 ◽  
Author(s):  
Chaoming PANG ◽  
Xinxin MENG ◽  
Chunpeng ZHANG ◽  
Jinlong PAN
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Thermal Insulation ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Dry Density ◽  
Core Shell ◽  
Aggregate Concrete ◽  
The Core

Abstract Shrinkage of foam concrete can easily cause cracking and thus makes it difficult for a manufacturer to maintain quality. The density of lightweight aggregate concrete is too high to meet specifications for lightweight and thermal insulation for wallboard. Two types of concrete with dry density in the range 1000–1200 kg/m3 for use in wallboard were designed and prepared using foam and lightweight aggregate. The properties of porous lightweight aggregate concrete with core-shell non-sintered lightweight aggregate were compared with sintered lightweight aggregate concrete along with several dimensions. The two aggregates were similar in particle size, density, and strength. The effects of each aggregate on the workability, compressive strength, dry shrinkage, and thermal conductivity of the lightweight concrete were analyzed and compared. Pore structures were determined by mercury intrusion porosimetry and X-ray computed tomography. Compressive strength ranged from 7.8 to 11.8 MPa, and thermal conductivity coefficients ranged from 0.193 to 0.219 W/m/K for both types of concrete. The results showed that the core-shell non-sintered lightweight aggregate bonded better with the paste matrix at the interface transition zone and had a better pore structure than the sintered lightweight aggregate concrete. Slump flow of the core-shell non-sintered lightweight aggregate concrete was about 20% greater than that of the sintered lightweight aggregate concrete, 28d compressive strength was about 10% greater, drying shrinkage was about 10% less, and thermal conductivity was less. Porous lightweight aggregate concrete using core-shell non-sintered lightweight aggregate performs well when used in wallboard because of its low density, high thermal insulation, and improved strength.

scholarly journals Utilization of Cementitious Materials with Cold-bonded Artificial Aggregate in Concrete

2019 ◽  
Vol 9 (1) ◽  
pp. 385-388
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Lightweight Aggregate Concrete ◽  
Optimum Level ◽  
Aggregate Concrete ◽  
Glass Fibres ◽  
Granulated Blast Furnace Slag

This article investigates the slump and compressive strength of artificial lightweight aggregate concrete with Ground Granulated Blast Furnace Slag (GGBFS) and Silica Fume with glass fibres. The increase in usage of cement in the construction industry is a concern for ecological deterioration, in this view; artificial aggregates was manufactured with major amount of fly ash and replacement of cement with various industrial by-products in concrete. An optimum level of GGBFS from 10 to 50% and Silica Fume from 2 to 6% with addition of glass fibres was assessed based on compressive strength values. The compressive strength was conducted for 7 and 28Days of water curing on M30 grade lightweight concrete with constant water to cement ratio as 0.45 and 0.2% of Master Gelenium super plasticizer. The conclusions achieved from the compressive strength of concrete containing GGBFS and Silica Fume was increased as the curing time increases. As a result lightweight aggregate concrete with a cement content of 226 kg/m3 develops 37.3 N/mm2 compressive strength.

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