scholarly journals Use of Preplaced Casting Method in Lightweight Aggregate Concrete

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Qiang Du ◽  
Qiang Sun ◽  
Jing Lv ◽  
Jian Yang

This study addresses the use of preplaced casting method in lightweight aggregate concrete (LC) to provide a new perspective to solve the aggregate segregation. In casting preplaced lightweight aggregate concrete (PLC), the lightweight aggregates are cast into formworks and then fresh grout is injected to fill voids. PLC and conventional lightweight aggregate concrete (CLC) with three different mixtures are compared to observe the degree of segregation. The properties of PLC and CLC are characterized by means of cubic and axial compression, splitting tension and flexural tests, static modulus of elasticity, and drying shrinkage measurements. Results show that the mechanical properties of PLC are improved with respect to that of CLC with the same mixture. The increase of shrinkage is approximately 13% for the CLC and 6% for PLC when w/c ratio ranges from 0.4 to 0.5 due to effect on interlocking. PLC shows an increased tendency in elastic modulus by approximately 2.5% of 0.5 w/c ratio, 2.7% of 0.45 w/c ratio, and 3.3% of 0.4 w/c ratio at the age of 28 days compared with CLC. In conclusion, PLC has significant reduction in the weight on the premise that it shows excellent mechanical properties.

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.


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