US EPA

6872432 

Journal Article 

Optimisation of using lightweight aggregates in mitigating autogenous deformation of concrete 

Akcay, B; Tasdemir, MAli; , 

2009 

Yes 

Construction and Building Materials
ISSN: 0950-0618
EISSN: 1879-0526 

ELSEVIER SCI LTD 

OXFORD 

353-363 

10.1016/j.conbuildmat.2007.11.015 

WOS:000265086000041 

Experiments were conducted to determine the effects of using dispersed saturated lightweight aggregates (LWAs) as water reservoirs in mitigating the autogenous deformation of high performance concrete and to establish the optimum solutions as a combination of a number of factors affecting the fracture and mechanical characteristics of concrete. For this purpose, in concretes prepared with a constant low water to cement ratio, normal aggregates were replaced by natural LWAs with size fractions of 2-4 mm or 4-8 mm at three different volume fractions such as 10%, 20% and 30% of the total aggregate volume of concrete. The results indicate that the inclusion of. ne fraction of LWAs in concrete reduces the autogenous deformation significantly compared to that of the coarse fraction. It is also shown that concretes with. ne fraction of LWAs have enhanced fracture and mechanical properties compared to those with coarse fraction of LWAs. Increasing the replacement ratio of LWAs mitigates autogenous deformation, while having an unfavourable effect on fracture and mechanical properties of concrete for both size replacements. A multi-objective simultaneous optimisation technique, in which the response surface method (RSM) is incorporated, is used to optimise the mitigation ratio of autogenous deformation and fracture parameters of high strength concretes in an effort to obtain a more ductile concrete with less autogenous deformation. (C) 2007 Elsevier Ltd. All rights reserved.