Durability aspects of HVFA-based recycled aggregate concrete

Abstract

The utilisation of recycled coarse aggregate obtained from demolished concrete has gained momentum in recent years due to its contribution towards sustainability by minimising the use of artificially produced materials and eliminating environmental problems due to dumped waste materials. The present research exploited the possibility of producing high-volume fly ash (HVFA)-based recycled aggregate (RA) high-strength concrete. It was found that 50% of desired strength could be achieved even with 50% replacement of cement with fly ash and 50% of natural aggregate (NA) with RA. An attempt was thus made to study the effects of RA and HVFA on durability characteristics. The parameters considered were resistance to chloride ion penetration, acid attack, sulfate attack and sorption. It was found that replacement of NA with RA and cement with fly ash in higher volumes showed a way of considering economy and environmental effects as criteria, given a little bit of compromise towards strength and durability criteria but still falling well within an acceptable limit.

Surface modified used rubber tyre aggregates: effect on recycled concrete performance

“…Like recycled construction or demolition aggregate (Gokce and Simsek, 2013;Hansen and Narud, 1983;Poon et al, 2004;Ravindrajah et al, 2006;Saravanakumar and Dhinakaran, 2014;Singh et al, 2013;Yang et al, 2011b), recycled waste tyre rubber within concrete can be a feasible option for sustainable and ecofriendly construction. Although the existing literature has considered different aspects with regards to the properties of rubber concrete, the general consensus is that the use of crumb rubber as aggregate in concrete will reduce its workability and strength, but will improve its ductility, impact resistance and dynamic energy dissipation capacity, and this is attributed to the rubber aggregate's own properties of high resilience and low density.…”

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).…”

Strength and Durability Studies on Geopolymer Recycled Aggregate Concrete

“…The strength improvement of control concrete was found as 31% from 7 to 28 days whereas for geopolymer concrete it was noticed as 11%. In geopolymer concrete most of the geopolymerisation reaction happens within the first few days of the curing [12,24,25]. The strength attainment was further accelerated in geopolymer concrete with 25%, 50% and 100% RCA the strength increment was found 8%, 6% and 5% respectively from 7 to 28 days.…”

“…For the sustainable development, construction and demolition waste materials and industrial wastes were used in concrete. The reduction in workability with the increase in the recycled coarse aggregate has been very much avoided with the addition of chemical admixture and using saturated surface dry (SSD) aggregates [1,2]. Geopolymer concrete has become the recent interest of civil engineers mainly due to their strength and durability properties and it reduced the CO2 emission [3 -7].…”