Abstract
The main application of concrete waste is its use as a coarse aggregate in concretes. Recycled concrete fines can be also used in concrete mixtures as fine aggregates or fillers. The paper describes an efficient activation method of recycled concrete fines to obtain technological, economical and ecological benefits. The idea is to combine mechanical and chemical methods of activation. According to various experiments the addition of superplasticizer into the mill speeds up grinding process. The present investigation shows that adding 0.5% by mass of recycled concrete fines allows obtaining higher specific area at the same processing time. Use of the prepared filler in SCC increases compressive strength more than 10% in compare with SCC containing limestone powder and mechanically activated recycled concrete fines.
Highlights
Mechano-chemical activation is an effective method of obtaining low water demand binders and active fillers for concretes
Superplasticizer Melflux 5581F was used during mechano-chemical activation of concrete grinding fines
Superplasticizer used in self-compacting concretes (SCC) composition was Sika ViscoCrete S 600 SP
Summary
Mechano-chemical activation is an effective method of obtaining low water demand binders and active fillers for concretes. Higher specific area for cement and other active materials provides higher chemical reactivity [2]. Concrete based on mechanically activated cement with specific area more 0.4 m2/kg has higher compressive strength on 7, 14 and 28 day of hardening [3]. The main problem of superfine cements and fillers is high water demand, so that obtaining mortars with good flowability and high compressive strength becomes impossible [4, 5]. Self-compacting concrete provides such benefits as reduction of construction time and labour cost, refusal of vibration, reduction of noise pollution, high compressive strength and dense structure [11, 12, 13]. Application of mechanochemically activated concrete grinding fines will improve rheological properties of SCC mix, and increase compressive strength of hardened concrete
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