scholarly journals Shrinkage and Strength Properties of Coal Gangue Ceramsite Lightweight Aggregate Concrete

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yunsen Wang ◽  
Jingping Qiu ◽  
Chao Zeng
Keyword(s):  
Waste Treatment ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
Strength Properties ◽  
Coal Gangue ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Concrete Shrinkage ◽  
Strength Tests ◽  
The Stability

It is a promising and effective method for waste treatment by using coal gangue to make lightweight aggregate concrete. However, lightweight aggregate concrete with low-density coal gangue ceramsite is prone to cracking during volume shrinkage, which limits its application in the construction industry. In an attempt to resolve the problem of cracking in shrinkage, this study investigated the effect of prewetting time and shrinkage reducing agents on shrinkage volume and concrete strength through a series of concrete shrinkage and strength tests. The experimental results show that shrinkage volume reduced at a prewetting time of 12 hrs or with a 2% addition of D-230 polyether amine reductant. With the optimal conditions of 12 hrs prewetting time and 2% addition of the reductant, the concrete shrinkage volume significantly decreased with a negligible impact on its strength. Appropriate amount of shrinkage reducing agent and adjustment of prewetting time of coal gangue ceramsite are necessary to reduce the shrinkage rate and improve the stability of the specimen. This is of great significance to wide application of lightweight aggregate concrete with coal gangue ceramsite.

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 .

scholarly journals Size Effect in Compressive Strength Tests of Cored Specimens of Lightweight Aggregate Concrete

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1187 ◽  
Author(s):  
Lucyna Domagała
Keyword(s):  
Compressive Strength ◽  
Scale Effect ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Cement Matrix ◽  
Lightweight Aggregate Concrete ◽  
Core Diameter ◽  
Aggregate Concrete ◽  
Normal Weight Concrete ◽  
Strength Tests

The aim of this paper is to discuss the unrecognized problem of the scale effect in compressive strength tests determined for cored specimens of lightweight aggregate concrete (LWAC) against the background of available data on the effect for normal-weight concrete (NWAC). The scale effect was analyzed taking into consideration the influence of slenderness (λ = 1.0, 1.5, 2.0) and diameter (d = 80, 100, 125, and 150 mm) of cored specimens, as well as the type of lightweight aggregate (expanded clay and sintered fly ash) and the type of cement matrix (w/c = 0.55 and 0.37). The analysis of the results for four lightweight aggregate concretes revealed no scale effect in compressive strength tests determined on cored specimens. Neither the slenderness, nor the core diameter seemed to affect the strength results. This fact should be explained by the considerably better structural homogeneity of the tested lightweight concretes in comparison to normal-weight ones. Nevertheless, there were clear differences between the results obtained on molded and cored specimens of the same shape and size.

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.

scholarly journals Numerical simulation of shear capacity of lightweight aggregate concrete stud connectors

2021 ◽  
Vol 272 ◽  
pp. 02021
Author(s):  
Hao Lin ◽  
Liu Lei ◽  
Li Jian
Keyword(s):  
Finite Element ◽  
Concrete Strength ◽  
Lightweight Aggregate ◽  
Shear Capacity ◽  
Parameter Analysis ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Finite Element Software ◽  
Stud Connector

In order to study the mechanical properties of the stud connectors in lightweight aggregate concrete (LWAC), the finite element software ABAQUS was used to establish the push test models of ordinary concrete and LWAC, respectively. Through parameter analysis of 21 models, the influence of different parameters on the shear performance of LWAC stud connector was studied. Among them, concrete strength, stud diameter and stud strength have strong effects. Compared with stud connector in ordinary concrete, the LWAC stud connector enters the elastoplastic working stage earlier, the ultimate slip is slightly larger, the ductility is better, and the shear capacity is about 11% lower. Regression analysis was performed on the finite element calculation results, and the method for shear bearing capacity calculation of the stud connectors in LWAC is given.

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

Study on Self-Igniting Gangue Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 2219-2224
Author(s):  
Mei Zhou ◽  
Xiao Fan Zhang ◽  
Feng Jiao Guan ◽  
Zhen Shuang Wang
Keyword(s):  
Sustainable Development ◽  
Portland Cement ◽  
Coarse Aggregate ◽  
Design Method ◽  
Lightweight Aggregate ◽  
Coal Gangue ◽  
Mix Design ◽  
Target Strength ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete

Self-igniting gangue concrete from C15 to C40 was successfully produced with fine and coarse aggregate of coal gangue through mix design method of lightweight aggregate concrete. It concluded that Self-igniting gangue concrete with reasonable grading can reach to the target strength. The basic properties of Self-igniting gangue concrete between Coal Gangue Portland cement and Portland cement were investigated, and mechanism was analysis. The coal gangue content was from 705 to 80% in the concrete. The technology can not only relief the scarcity of natural aggregate, but also employed the solid waste, and it was suitable for sustainable development in 21 century.

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