Investigation on influence of size of aggregate and effect of strength on altering the ratio in low nominal concrete mixes

Abstract

Concrete is rapidly changing because concrete for the 21st century must be stronger, more durable, more constructible, more environmentally friendly, more practicable and more cost-effective. The main aim of this research work was to investigate the influence of aggregate size and their effect on strength by altering the available nominal concrete mix ratios. And also this research studies would give consciousness among researchers, engineers and the public about increase in strength while altering the conventional mix of M5 and M 7.5 concrete grades. This investigational study was carried out on 7.5 and M5 concrete grades, which are used for masonry wall foundations and concrete bases with the lean mix. For identifying the effect of strength, concrete prepared with M5 grade conventional mix (1:5:10) to 1:5:9 & 1:5:8 and M7.5 grade conventional mix (1:4:8) to 1:4:7 & 1:4:6 along with 40 mm downgraded coarse aggregate and 53 grade cement. The relative clause of these above concrete mixes was studied. And the effect of using 40% of 20 mm size aggregate and 60% of 40 mm aggregate for the above nominal concrete mixes were also studied. Concrete mix with ratio 1:5:8 was stronger than the 1:5:10 mix by about 3.5 times and concrete mix with ratio 1:4:6 was stronger than the 1:4:8 mix by about 5 times. The relative cost was increased for the above two mixes by 2.56% and 4.05% respectively.