Study on early autogenous shrinkage and crack resistance of fly ash high-strength lightweight aggregate concrete

Abstract

A self-designed test and the elliptical ring test were applied to test the early autogenous shrinkage and crack resistance of fly ash high-strength lightweight aggregate concrete in which 10-30% of cement was replaced by equivalent amounts of fly ash of different fineness. Test data of reference lightweight aggregate concrete were provided. The results showed that (a) the early autogenous shrinkage of concrete was restrained in fly ash highstrength lightweight aggregate concrete, and further analysis indicated higher fly ash content and higher fly ash fineness resulted in less autogenous shrinkage; (b) in a lower water-binder ratio, early autogenous shrinkage increased significantly as the water-binder ratio decreased, and, moreover, pre-wetting of lightweight aggregate had a great effect on controlling early autogenous shrinkage; (c) the elliptical ring test results indicated that the addition of fly ash significantly improved crack resistance of lightweight aggregate concrete and that this improvement becomes obvious with increasing fineness of fly ash. Therefore, in practice, the addition of fly ash could be a technical alternative to reduce early autogenous shrinkage and to enhance the crack resistance of lightweight aggregate concrete.

Effect of chemical treatment of MSWI bottom ash for its use in concrete

“…Efforts have focused on the use of bottom ash as a replacement for aggregate or cement. Unlike successful applications of other recycled materials in concrete such as recycled aggregate concrete (Gökçe and Ş imşek, 2013;Saravanakumar and Dhinakaran, 2014), coal fly ash (Gao et al, 2013;Wang, 2013) and others (Ahmadi et al, 2014;Ferreira et al, 2014;Kwan et al, 2013), not many successful uses of ash addition have been reported. This is mainly due to the side effect caused by the chemical reaction of aluminium in a high alkaline environment (Aubert et al, 2004;Bertolini et al, 2004;Müller and Rübner, 2006;Rubner et al, 2008).…”

Investigations on Flexural and Compressive Strengths of Mortar Dedicated to Clinker Units—Influence of Mixing Water Content and Curing Time

“…The effect of the additive in the form of fly ash on the amount of spontaneous shrinkage, micro crack formation, and fracture toughness is known. For example, it was also analyzed in relation to lightweight aggregate concretes [ 25 ].…”

Assessment of behaviour and cracking susceptibility of cementitious systems under restrained conditions through ring tests: A critical review

“…The above-mentioned authors performed numerous studies [90][91][92][93][94][95][96][97] in order to investigate the effects of steel and concrete ring thicknesses, minor and major radius of the ellipse, as well as drying direction to argue that depending on the geometry used, cracking initiation is reduced and its location can be well predicted. It should be mentioned that although this method has been proposed to replace the standardised ring test, it has only been used by its conceptors so far (with the exception of [98]) and therefore it may be considered that it is still under development.…”