CDW RECYCLED AGGREGATES FOR DRY CAST CONCRETES. Sérgio Angulo

Transcrição

1 CDW RECYCLED AGGREGATES FOR DRY CAST CONCRETES Sérgio Angulo

2 BACKGROUND Most of production of aggregates is destined for cementitious materials. The consumption of aggregate in dry cast concrete represents the 24% of Brazilian total aggregates' consumption Dry cast concretes are ecoefficient compaction permits reduction of water and cement consumption.

3 ECOEFFICIENCY IN CONCRETE 20,0 Literature - Brazil BI (kg.m-3.mpa-1) 17,5 Literature - International Site mixing 15,0 Ready-mix concrete 1 Ready-mix concrete 2 12,5 Waste 10,0 Ready mix plastic Rolled 7,5 5,0 2,5 250kg/m³ 0, Compressive strenght (MPa) DAMINELI, B. L. KEMEID, F. M. AGUIAR, P. S.; JOHN, VANDERLEY M. Measuring the eco-efficiency of cement use. Cement and Concrete Composites, v. 32, n. 8, p , 2010.

4 DRY CAST CONCRETES Strength and porosity of dry concretes are governed by mobility of dry mix and quality of aggregates TUCEK e BARTAK (1991) adaptado

5 MOBILITY OF DRY MIX Influenced by particle size distribution of aggregates LARRARD (1999); OLIVEIRA et al. (2000)

6 Sieving WAYS TO IMPROVE MOBILITY OF DRY MIX Heterogeneous and porous CDW recycled aggregates are sieved in many particle size fractions

7 CDW RECYCLED AGGREGATES Cement paste (porous) D < 2,0 g/cm³ Cement- Granite (non liberated) 2,0 < D < 2,6 g/cm³ Granite (non porous) D > 2,6 g/cm³ ABS > 15% 15% < ABS < 5% ABS < 5% Bricks D < 1,5 g/cm³ Blocks 1,5 < D < 1,9 g/cm³ Tile/shingle D > 1,9 g/cm³ ANGULO (2005) tese doutorado ABS > 24% 24% < ABS < 14% ABS < 14%

8 WAYS TO IMPROVE CDW RECYCLED AGGREGATES Thermal treatment and/or milling Weaken porous cement paste (cracks) Selective comminution of porous cement paste (softer phase). Natural granite aggregates (harder phase)

9 WAYS TO IMPROVE CDW RECYCLED AGGREGATES

10 WAYS TO IMPROVE CDW RECYCLED AGGREGATES Density separation of porous particles Gravity separation using wet jigs. Light fraction is a mixed fraction of red ceramic and cementitious particles. It contains higher porosity. Heavy fraction is also mixed, but with higher amount of natural rock aggregates. It contains lower porosity. Crushing of porous particles Destroy porosity of cement and red ceramic porous particles. Transform coarse fraction into less porous sand or powder fraction.

11 WAYS TO IMPROVE CDW RECYCLED AGGREGATES

12 Objective of Research Compare characteristics of dry cast concretes formulated with CDW aggregates obtained from different recycling strategies (sieving and density/crushing).

13 0,000 0,010 0,020 0,030 0,040 0,050 0,060 0,070 0,080 0,090 0,100 Representative mass (kg) Experimental Planning Sampling CDW recycled aggregates (< 9 mm) Mass reduction (horizontal piles) Representative mass (Pierre Gy theory) d95=32 mm d95=16 mm d95=4 mm DOI /s Concentration of organic materials (in kg/kg)

14 Experimental Planning Density Separation 20 kg of CDW aggregates Operation conditions With fines (< 2mm) or not Pressure (0,01 0,1 bar) Frequency (50-90 rpm) Mass recovery analysis for each layer Envelope density determination ED = Mass / [V solid + Vpores] LEPECHUKA (2013)

15 Massa acumulada (%) Results (Density separation) 100 J1 J2 80 J3 J5 J7 J4 J6 J8 Pressure 0,01 bar Frequency 50 rpm Without fines 20 With fines 0 2,100 2,200 2,300 2,400 2,500 2,600 2,700 Massa específica aparente - média Geopyc (g/cm³) LEPECHUKA (2013)

16 Experimental Planning Lab test CDW recycling routes

17 Experimental Planning Characterization of aggregates Particle Size Distribution and shape analysis Porosity (mercury intrusion) Density and water absorption (std methods) Dynamic Image Analysis

18 Distribuição volumétrica acumulada (%) Distribuição volumétrica acumulada (%) Results densa leve mista areia de cava areia de brita areia de calcário pó de pedra pedrisco ,4 0,5 0,6 0,7 0,8 0,9 1 Esfericidade densa leve mista areia de cava areia de brita areia de calcário pó de pedra pedrisco ,3 0,5 0,7 0,9 Relação de aspecto

19 Results Agregados Absorção de água (% kg/kg) Massa Específica Aparente (MEA) (kg/dm³) Massa Específica Real (MER) (kg/dm³) Porosidade [(1 MEA/MER)x100] (%) Areia densa 5,99 ± 0,06 2,37 ± 0,01 2,67 ± 0,01 11,2 de RCD Areia leve de 10,28 ± 1,25 2,07 ± 0,02 2,63 ± 0,13 21,3 RCD Areia mista 9,72 ± 0,45 2,02 ± 0,02 2,52 ± 0,01 19,8 de RCD Areia cava 0,34 ± 0,11 2,62 ± 0,01 2,65 ± 0,01 1,1 Pó de pedra 1,08 ± 0,04 2,59 ± 0,01 2,66 ± 0,01 2,6 Pedrisco fino 0,97 ± 0,01 2,61 ± 0,01 2,67 ± 0,01 2,2

20 Experimental Planning Concreto seco com areia mista de RCD (CS-AM) Material Traço Massa (%) Volume (%) Cimento (CP V 40) 1,00 16,67 11,53 Areia mista de RCD 5,00 83,33 88,47 Total 6,00 100,00 100,00 Concreto seco com areia densa e leve de RCD (CS-AD&L) Material Traço Massa (%) Volume (%) Cimento (CP V 40) 1,00 15,38 11,51 Areia leve de RCD 2,50 38,46 43,11 Areia densa de RCD 3,00 46,15 45,38 Total 6,50 100,00 100,00 Concreto seco de referência, com agregado natural (CSR-AN) Material Traço Massa (%) Volume (%) Cimento (CP V 40) 1,00 13,33 11,66 Areia cava 0,65 8,67 8,86 Pó de pedra 1,30 17,33 17,66 Pedrisco 4,55 60,67 61,82 Total 7,50 100,00 100,00

21 Volume retido (% cm³/cm³) Particle size distribution of dry mixes 14% 12% 10% mistura cimento:agregados naturais mistura cimento:areia densa e leve de RCD mistura cimento:areia de RCD misto 8% 6% 4% 2% 0% Abertura da malha (µm)

22 Compression of Mixes (force and displacement)

23 Results Massa específica do concreto (Kg/dm³) 2,40 2,35 2,30 2,25 2,20 2,15 2,10 2,05 2,00 1,95 1,90 2,33 2,33 2,34 2,13 2,08 2,04 1,97 1,96 CSR-AN CS-AD&L CS-AM 2,08 2,09 2,00 1, Umidade (%)

24 Carga (N) Results CS-AM CS-AD&L CRS-AN Deslocamento do pistão (mm)

25 Porosity (% dm³/dm³) Results CS-AM Cs-AD&L CSR-NA Pores -before compaction Pores - after compaction

26 Resistência à Compressão (MPa) Results média 3 dias média 7 dias média 28 dias CS-AM CS-AD&L CSR-AN

27 Distribuição volumétrica (%) Distribuição volumétrica (%) Distribuição volumétrica (%) Experimental Planning CONT-M 6 DESC-M Tamanho da partícula (mm) Tamanho da partícula (mm) DESC-LD REF Tamanho da partícula (mm)

28 Experimental Planning

29 Results

30 Results

31 Conclusions Reduction of CDW recycled aggregate porosity and gap-graded particle size distribution improve dry cast concrete performance. A sieving CDW recycling plant has lower environmental impact and it is a cheaper solution, being a more ecofficient CDW recycling solution. Lab tests can be used to understand behaviour during compaction.

32 Bibliography QUATTRONE, MARCO ; ANGULO, SERGIO C. ; JOHN, VANDERLEY M.. Energy and CO2 from high performance recycled aggregate production. Resources, Conservation and Recycling, v. 90, p , SILVA, R. B. ; ANGULO, S. C. ; PILEGGI, R. G. ; SILVA, C. O.. Concretos secos produzidos com agregados reciclados de RCD separados por densidade. Artigo em revisão. Revista Ambiente Construido Nakano,AY.;Torres,DR.; Grandes,FA.; Maia, FT;Fujitaki, GJ. Estudo da viabilidade do uso de resíduos da construção e demolição na fabricação de peças intertravadas de concreto Trabalho de Conclusão de Curso (Graduação em Engenharia Civil) - Universidade de São Paulo. ULSEN, C. ; KAHN, H. ; HAWLITSCHEK, G. ; MASINI, E.A. ; ANGULO, S.C. ; JOHN, V.M.. Production of recycled sand from construction and demolition waste. Construction & Building Materials, v. 40, p , ANGULO, S. C. ; JOHN, V. M. ; ULSEN, C. ; KAHN, H. ; MUELLER, A.. Separação óptica do material cerâmico dos agregados mistos de resíduos de construção e demolição. Ambiente Construído (Online), v. 13, p , LEPECHUKA, V. O. PRODUÇÃO DE AGREGADOS GRAÚDOS RECICLADOS DE BAIXA POROSIDADE EM JIGUE DE ESTRATIFICAÇÃO LABORATORIAL. Trabalho de Conclusão de Curso DAMINELI, B. L. KEMEID, F. M. AGUIAR, P. S.; JOHN, VANDERLEY M. Measuring the eco-efficiency of cement use. Cement and Concrete Composites, v. 32, n. 8, p , ANGULO, S. C.; MUELLER, A.. Determination of construction and demolition recycled aggregates composition, in considering their heterogeneity. Materials and Structures, v. 42, p , 2009.