Investigation of Self-Compacting Concrete by Using Fracture Mechanics Methods

Abstract

Over a century, concrete has been used as a construction material all over the world, andits application areas increases and becomes commonplace each day. SCC is a special concretetype which places itself in densely-equipped narrow and deep sections with its own weight,tightens without any vibrations, has high resistance or durability characteristics andperformances, and has a very fluid- consistency. Fracture Mechanics researches defects that increase stress concentration such as notch, crack and flaws in the material and the damages occurring in relation to these defects. Therefore, a cracked construction could be analyzedonly by using fracture mechanics methods, that is, by determining fracture parameters realistically. Fracture parameters are among the most important characteristics of hardenedconcrete. In this study, SCC was investigated via the two-parameter fracture model whichneeds two fracture parameters namely: the critical stress intensity factor KIcs and the criticalcrack mouth opening displacement CTODc to characterize failure of concrete structures. InSCC mix, silica fume, fly ash and marble powder were used as powder materials. Sincephysical characteristics of the powder materials used are different, fresh concretecharacteristics of the series display differences. Water curing was applied to all the concretespecimens. Although concrete mix ratio and storage conditions of all series are the same,powder admixture type affected concrete compressive strength. It is known that there is aclose relation between concrete compressive strength and fracture parameters. Based onmaximum loads of SCC specimens produced with different powder materials, critical stressintensity factor KIcs and critical crack tip opening displacement CTODc, fracture parameterswere determined. Consequently, it was observed that concrete compressive strength andpowder admixture type are effective on fracture parameters of concrete.