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.

Preparation Test Study on High Strength Lightweight Concrete in Engineering Materials

2013 ◽  
Vol 648 ◽  
pp. 55-58
Author(s):  
Xiao Qing Yu ◽  
Mao Lin ◽  
Guang Long Geng ◽  
Yue Han Li ◽  
Li Jia
Keyword(s):  
Rate Ratio ◽  
Coarse Aggregate ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Cement Ratio ◽  
Test Study ◽  
Aggregate Rate

Low and easy brittle characteristics of lightweight aggregate concrete tensile strength, shear strength, combined with high strength lightweight concrete requirements in the selection select strength Lytag, silica fume, superplasticizer material, preparationhigh strength lightweight aggregate concrete. Experimental study on the water-cement ratio, coarse aggregate rate ratio factors on the strength of lightweight aggregate concrete.

scholarly journals Ductility and internal forces redistribution in lightweight aggregate concrete beams

2020 ◽  
Vol 19 (4) ◽  
pp. 095-108
Author(s):  
Tomasz Waśniewski ◽  
Ewelina Kołodziejczyk
Keyword(s):  
Cross Sections ◽  
Degrees Of Freedom ◽  
Lightweight Concrete ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Brittle Behavior ◽  
Structural Applications ◽  
Internal Forces

Lightweight Aggregate Concrete (LWAC) is typically defined as concrete having a density smaller than or equal to 2200kg/m3 and can be obtained by mixing natural or artificial lightweight aggregates. There is a general scepticism regarding the use of lightweight aggregate concrete (LWAC) for structural applications. This concern is attached to the more brittle material behaviour which leads to lower ductility. This article presents a numerical parametric analysis of the behaviour of the reinforced LWAC cross-sections under the immediate load taking into account the density of the LWAC concrete, concrete strength and tensile reinforcement ratio. Numerical analysis of  the beams was conducted in OpenSees, an open–source nonlinear finite element method framework. One-dimensional elements, with three degrees of freedom at each end, were used. Bending stiffness in the integration points was calculated based on the sectional moment – curvature relationship. The analysis showed that there is a relationship between the ductility of the cross-sections made of lightweight concrete and its density class. It is associated with limited compressive strains and the brittle behavior of LWAC. The limited rotation capacity of the reinforced concrete sections made of LWAC also affects the ability of redistribution of internal forces in statically indeterminate beams

Research on Porous Properties of Air-Entrained Lightweight Aggregate Concrete

2013 ◽  
Vol 652-654 ◽  
pp. 1209-1212
Author(s):  
Wei Xin Hu ◽  
Abulitipu. Abudula
Keyword(s):  
Thermal Conductivity ◽  
Porous Structure ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Materials Properties ◽  
Porous Properties ◽  
Concrete Materials ◽  
The Right

Lightweight aggregate concrete with bleed air : the air-entraining agent added to the lightweight aggregate concrete , cement paste to form the porous structure of the porous structure of the right amount of artificial lightweight aggregate concrete . Reduce the density of the concrete to improve the insulation properties of the concrete . Applied to structural insulation concrete strength than 20Mpa, the thermal conductivity is less than 0.36W / ( m • K) . Of lightweight aggregate structure insulation concrete materials properties and microstructure of variation with air entraining agent .

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.

scholarly journals Characterization of lightweight concrete made of palm oil clinker aggregates

2018 ◽  
Vol 250 ◽  
pp. 03002 ◽  
Author(s):  
Muhammad Sazlly Nazreen ◽  
Roslli Noor Mohamed ◽  
Mariyana Aida Ab Kadir ◽  
Nazry Azillah ◽  
Nazirah Ahmad Shukri ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Palm Oil ◽  
Lightweight Concrete ◽  
Flexural Modulus ◽  
Pulse Velocity ◽  
Normal Weight ◽  
Lightweight Aggregate Concrete ◽  
Fine Aggregate ◽  
Test Results ◽  
Aggregate Concrete

Lightweight concrete (LWC) has been identified as an innovative technique for construction purposes. Lightweight concrete can be categorized into three different types which are no-fine aggregate concrete, lightweight aggregate concrete and aerated concrete. This paper studied the characteristic of the lightweight concrete in term of mechanical properties utilizing the palm oil clinker (POC) as lightweight aggregates. Two mixes of lightweight concrete were developed, namely as POCC100 and POCC50 where each mix utilized 100% and 50% of total replacement to fine and coarse aggregates, respectively. The fresh and hardened POC concrete was tested and compared to the normal concrete (NC). The hardened state of the concrete was investigated through density test, ultrasonic pulse velocity, cube compressive, splitting tensile, flexural, modulus of elasticity and Poisson's ratio. From density test results, POC falls into the category of lightweight concrete with a density of 1990.33 kg/m3, which are below than normal weight concrete density. The mechanical properties test results on POCC100 and POCC50 showed that the concrete compressive strength was comparable about 85.70% and 96% compared to NC specimen, respectively. For the flexural strength, POCC50 and POCC100 were comparable about 98% and 97% to NC specimen, respectively. While splitting tensile strength of POCC50 and POCC100 was only 0.6% and 4% lower than NC specimen, respectively. In terms of sustainability of solid waste management, the application of the POC in construction will reduce the redundant of by-products resulted from the palm oil industries. After undergoing various testing of concrete mechanical properties, it can be concluded that POC aggregates was compatible to be used in ligtweight concrete mix proportion.

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