Effect of aggregate grading on the fresh and mechanical performance of recycled aggregate self-compacting concrete
- Vol.95(5), May
- Thane ACC LTD 2021
- 30-40p.
Due to the substantial boom in infrastructure growth in developing countries such as India, the supplies of natural aggregates (NAs) are declining at a high rate and thereby causing an ecological imbalance. Contrary to that enormous volume of recycled aggregates (RAs) created from the waste of building and demolition (C&D). Therefore, in terms of preservation, the use of RA in the construction of reinforced concrete can be a great source of aggregate. It is well known that aggregates occupy nearly 70 percent of the volume in concrete, and they help in optimizing the cement and water and thus enabling higher strengths while lowering the shrinkage, creep, and temperature effects in concrete. The shape, size, grading, and texture (of natural, artificial, and recycled types) affects the water needed for certain workability considerably. The grading and proportions of the individual coarse and fine aggregates (either in all-in aggregate grading or otherwise) affects workability and this influence is more pronounced when self-compacting concrete is used. In the present investigation, self-compacting concrete (SCC) was developed with complete substitution of coarse NAs with coarse RAs by employing the allin aggregate grading curves of DIN standards. Supplementary cementing materials (SCMs) such as coal fly ash (CFA), ground granulated blast furnace slag (GGBS), and metakaolin (MK) have also been used as cement substitute materials to make the SCC more sustainable. Finally, based on fresh properties such as slump flow, T500, V-funnel, and L-box test, and mechanical properties through compressive strength test, a comparison is made for concrete with the use of DIN combined grading against the all-in grading curve defined in the BIS code. It is concluded that, especially in the presence of SCMs, the DIN all-in aggregate grading provides better workability and mechanical performance for SCCs compared to BIS all-in aggregate grading method.