Influence of elevated temperatures on the mechanical properties and microstructure of self consolidating lightweight aggregate concrete

2012 ◽  
Vol 34 ◽  
pp. 575-583 ◽  
Author(s):  
Özge Andiç-Çakır ◽  
Selim Hızal
2020 ◽  
Vol 10 (10) ◽  
pp. 3519 ◽  
Author(s):  
Chao-Wei Tang

In this study, the effects of individual and mixed fiber on the mechanical properties of lightweight aggregate concrete (LWC) after exposure to elevated temperatures were examined. Concrete specimens were divided into a control group (ordinary LWC) and an experimental group (fiber-reinforced LWC), and their compressive strength, elastic modulus, and flexural strength after heating to high temperatures of 400–800 °C were investigated. The four test parameters included concrete type, concrete strength, fiber type, and targeted temperature. The test results show that after exposure to 400–800 °C, the variation in mechanical properties of each group of LWC showed a trend of increasing first and then decreasing. After exposure to 400 °C, the residual mechanical properties of all specimens did not attenuate due to the drying effect of the high temperature and the more sufficient cement hydration reaction. However, after exposure to 800 °C, the residual mechanical properties significantly reduced. Overall, the mixed fiber-reinforced LWC showed a better ability to resist the loss of mechanical properties caused by high temperature. Compared with the loss of compressive strength, the flexural strength was relatively lost.


2018 ◽  
Vol 926 ◽  
pp. 140-145 ◽  
Author(s):  
Małgorzata Mieszczak ◽  
Lucyna Domagała

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.


2012 ◽  
Vol 28 (4) ◽  
pp. 147-156 ◽  
Author(s):  
Guiming Wang ◽  
Bin Zhang ◽  
Zhonghe Shui ◽  
Daoyi Tang ◽  
Yun Kong

It is of great significance to improve the flexibility of concrete for specific applications, such as a tunnel pavement or an airport runway. This paper presents the structural properties of the rubberized lightweight aggregate concrete at the macro- and micro-level. The relationship between mechanical properties and microstructure features was further explored. An experimental programme was developed to use crumb rubber and shale ceramsite to produce a flexible concrete. Much attention was paid to the influence of the crumb rubber dosage. The compressive strength and elastic modulus of the rubberized lightweight aggregate concrete were measured. Furthermore, the corresponding microstructure was evaluated by microhardness assessment and microscopic observation. Experimental results show that with the increase of crumb rubber dosage, the bonding interface between the rubber and cement paste, as well as between the shale ceramsite and cement paste, gradually became weakened or flexible. In addition, the width of the weak bonding interface became wider. As a result the flexibility of lightweight aggregate concrete can be effectively improved by correctly adjusting the crumb rubber dosage.


2011 ◽  
Vol 117-119 ◽  
pp. 1302-1305
Author(s):  
Ning Liao ◽  
Hong Zhi Cui

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.


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