ABSTRACT

The Self weight of the structures consists major portion of their overall weight. The use of lightweight concrete not only reduces the weight but a l so results in the reduction i n the
sections of the structural elements resulting in the economy. The concrete without fine aggregates is term ed as 'no-fines concrete', which i s one of the types of the lightweight concrete family. Normally no-fines concrete (NFC) i s produced with the crushed coarse aggregate of uniform gradation. Th is study is aims to investigate experimentally the effect of using uncrushed coarse aggregate on unit weight (density) and strength properties of no-fines concrete. The strength properties investigated are compressive strength, spilt cylinder tensile strength and flexural strength (Modul us of rupture). Four gradations of uncrushed coarse aggregates ranging between pacific maxim um and minimum size are used i.e. 5.5mm-4.75m m, 10mm-4.75mm, 20mm-4 .75mm and 25mm- 4.75mm Fixed cement: aggregate ratio I :6 is adopted for No-fines concrete while l :2:4 ratio is adopted for Normal concrete. The water cement ratio is maintained at a fixed value 0.4 for No-fines concrete and 0.5 for normal concrete thought the study. The results values are compared i n terms of effect of gradation of uncrushed coarse aggregates in no- fines concrete itself and normal concrete with same gradation of uncrushed coarse
aggregates.