Certification of Glass for Use in Concrete I Dr Belen Morales Manager ConGlassCrete II Project Centre for Cement and Concrete University of Sheffield
Two Main Areas of Work Waste Glass as Pozzolan Waste Glass as Pozzolan and Aggregate in Concrete Products (tests by CCC, Industrial Partners and BRE)
Glass Pozzolanicity Hypothesis Glass is composed of ~70% amorphous silica and therefore should, in a fine form, react with lime and water to produce hydrated cementitious products in a similar way to PFA, GGBS and microsilica
Chemistry of Waste Glass NUMBER GLASS TYPE SiO 2 OXIDE (MASS, %) Na 2 O CaO Al 2 O 3 K 2 O Fe 2 O 3 MgO 1 Plate (R) 71.25 13.44 9.15 1.15 0.47 0.40 3.05 2 Plate (R) 71.27 13.34 8.89 1.09 0.55 0.36 3.41 7 Windscreen (PC) 69.7 14.80 8.90 1.00 0.45 0.32 4.31 8 Car Windows (PC) 68.5 15.00 9.79 0.90 0.33 0.72 4.26 13 Blue (R) 72.91 13.41 10.65 1.99 0.46 <0.05 0.14 14 Green (R) 71.03 13.35 10.44 1.59 0.71 0.49 1.62 15 Amber (R) 71.27 13.41 9.85 1.98 0.77 0.53 2.12 16 Cullet (PC) 68.39 12.49 12.72 1.56 0.56 0.56 1.18 17 Cullet 1 (PC-washed) 68.13 12.42 12.69 1.60 0.54 0.43 1.26 18 Cullet (PC) 70.50 13.00 10.80 1.90 0.67 0.34 1.50 19 Cullet (PC) 69.5 14.40 11.40 1.75 0.63 0.33 1.41 20 Cullet (PC) 69.5 14.20 11.30 1.91 0.62 0.33 1.5 21 Cullet (PC) 69.6 13.90 11.40 1.95 0.66 0.39 1.44 22 Cullet (PC) 69.3 14.10 11.30 2.00 0.63 0.47 1.46 30 Fluores. tubes (PC) 70.79 16.07 5.25 1.85 1.06 0.30 3.14 31 Light bulb (R) 70.52 15.60 5.72 1.65 0.86 1.40 3.53 Average 70.14 13.93 10.02 1.62 0.62 0.49 2.21 GGBS 33-37 <0.4 38-43 8-14 <0.4 <1 <14 PFA 48-55 0.7-1.7 1-6 22-29 2-4 8-13 1-2 MS 86-94 <0.5 <0.4 <0.5 <0.7 <0.2 <1
Experimental Materials 33 Waste Glasses Tested NUMBER TYPE FINENESS RANGE (m 2 /kg) 1-5 Plate (R) 262-806 6 Plate (PC) 575 7-12 Windscreen and side-rear windows (PC) 278-695 13, 14 Single colour container (R) 361-458 15-27 Mixed colour container (PC) 250-876 28 Light bulbs (R) 587 29-33 Fluorescent Tubes (PC) 280-989 R-Rejected by glass Industry PC- Post-consumer
Contamination in Waste Glass CONTENT CONTENT (%) NUMBER GLASS TYPE (ppm) Cr 2 O 3 PbO SO 3 LOI Cl Sugars 1 Plate (R) <0.05 <0.05 0.10 0.25 a - - 2 Plate (R) <0.05 <0.05-0.38 a - - 7 Windscreen (PC) <0.05 <0.05-0.21 a -0.28 b <2 8 Car windows (PC) 0.05 <0.05-0.23 a -0.41 b 28 13 Blue (R) <0.05 <0.05 0.07 0.31 a - - 14 Green (R) 0.23 <0.05 <0.05 0.22 a - - 15 Amber (R) <0.05 <0.05 0.05 0.19 a - - 16 Cullet (PC) 0.06 <0.05 0.12 0.83 a 50.9 46 18 Cullet (PC) 1.13 <0.05 0.05 0.65 a 21.7 12 19 Cullet (PC) 0.12 <0.05-0.52 a -0.94 b - <2 20 Cullet (PC) 0.11 <0.05-0.46 a -0.82 b - <2 21 Cullet (PC) 0.14 <0.05-0.65 a -1.00 b - <2 22 Cullet (PC) 0.12 <0.05-0.66 a -1.00 b - <2 30 Fluores. tubes (PC) <0.05 <0.05 - - - - 31 Light bulb (R) 0.15 <0.05-0.17 - - a to BS 2646 (550ºC, 1h) b to BS 196-2 (975ºC, 2h)
Concrete Experiments Setting Times and Water Requirement TYPE INITIAL SETTING WATER FINENESS TIME a REQUIREMENT b (m 2 /kg) (30% cement replacement) Control 2.4h 100% Plate (R) 806.0 2.6h 95.5% Plate (R) 575.0 2.7h 95.5% Plate (R) 261.8 2.9h 100.0% Windscreen (PC) 376.5 3.2 100.0% Car windows (PC) 304.5 3.9h 100.0% Green (R) 458.1 2.7 97.8% Amber (R) 361.5 2.7 97.8% Cullet (PC) 245.8 3.0h 101.3% Cullet (PC) 247.3 3.1h 100.0% Cullet (PC) 269.7 3.1h 100.0% Cullet (PC) 264.8 2.8h 101.3% Fluor. Tubes (PC) 988.9 2.5h - Fluor. Tubes (PC) 281.1 2.7h 97.8% a BS 196-3 b BS 3892-1
Strength Development I (industrial sub-project) 80 (a) Green Glass Pozzolan 80 (b) Green glass pozzolan and sand Compressive strength (N/mm 2 ) 70 60 50 40 30 20 10 0 PC Control PC/GP10 PC/GP25 PC/GP50 0 80 160 240 320 400 Age (days) 70 60 50 40 30 20 10 0 PC Control PC/GGS 50 PC/GP10/GGS 50 PC/GP25/GGS 50 0 80 160 240 320 400 Age (days)
Strength Development II (laboratory mortar test to BS EN 450) Relative strength (%) 115 105 95 85 75 (a) 28 days of curing Surface area > 300m 2 /kg achieves BS EN 450 strength compliance BS EN 450 minimum relative strength 115 105 95 85 75 (b) 90 days of curing Surface area > 300m 2 /kg achieves BS EN 450 strength compliance BS EN 450 minimum relative strength 65 200 300 400 500 600 700 800 900 1000 Surface area (m 2 /kg) 65 200 300 400 500 600 700 800 900 1000 Surface area (m 2 /kg)
Possible Model Specifications PARAMETERS BS EN 450 BS 3892 ASTM C 618 Part 1 Part 2 Part 3 N F C SiO 2 +Fe 2 O 3 +Al 2 O 3, min % To be provided To be provided 70 70 50 Reactive SiO 2, min % 25% N/R N/R Total alkali contents (Na 2 O) To be provided To be provided 1.5 Total CaO, max % 10 + 1 10 + 1 N/R N/R N/R Free CaO, max % 1 N/R N/R Chloride, max % 0.1 0.1 N/R N/R N/R Sulfur trioxide (SO 3 ), max % 3 2 2.5 2.5 4 5 5 Loss on ignition, max % 5-7 a 7 12 14 10 6 6 Fineness (retained on 45µm sieve) max % 40 12 60 60 34 Strength Activity index, min. % of control (25% cement replacement) at 28 days 75% -5% a at 90 days 85% -5% a (30% cement replacement) at 28 days 80% -5% a (20% cement replacement) at 7 days 75% at 28 days 75% Soundness, max expansion (50% cement replacement) 10mm (30% cement replacement) 10mm (25% cement replacement) 0.8 autoclave expansion Particle density, min kgm -3 Max variation ±150kgm -3 2000 N/R Max deviation 5 % Moisture content, max, % N/R 0.5 3 Water requirement, max. % of (30% cement replacement) N/R control 95 115 105 105 Initial setting time (30% cement replacement) N/R Not less than cement N/R N/R not requirement a- National basic
Proposed Specification for Glass as Concrete Pozzolan PARAMETERS CRITERIA METHODS SiO 2, min % 68 BS 196-2 Chloride, max % 0.1 BS 196-21 Loss on ignition, max % 1.5 BS 196-2 Surface area, min m 2 /kg 300 BS 196-6 Activity index, min 75% at 28 days 85% at 90 days BS 196-1 Soundness, max expansion 10mm BS 196-3 Initial setting time, max 2h more than control BS 196-3 Lead, max % 0.1 BS 6748 a a-limits of metal release from glassware, glass ceramic and vitreous ware
Certification of Glass in Concrete Products From the 20 ConGlassCrete sub-projects, 3 products were selected for certification processes: Grey Blocks: glass aggregate and pozzolan Paving Blocks: glass pozzolan Masonry Units: glass aggregate
Grey Blocks PROPERTIES BS 6073-1 CRITERIA Dimensional Check Length Height Thickness +3mm - 5mm +3mm - 5mm ±2mm average ±4mm individual Compressive strength a) 7.0N/mm 2 b) 0.9*7.0 + 0.62*S a (N/mm 2 ) Transverse Strength 0.65 N/mm 2 Drying Shrinkage 0.06% a- Standard deviation
Paving Blocks PROPERTIES BS 6717 & BS EN 1338 CRITERIA Shape and Thickness <100mm: Dimensions Length & width ± 2m, thickness ± 3mm 3.9 N/mm 2 average Tensile Splitting 2.9 N/mm 2 individual Strength Individual breaking load 250 N/mm Class Degree of abrasion Abrasion Resistance A1 No performance determined A2 23mm Class Mean value S1 No performance determined Slip/Skid Resistance S2 35 C scale units S3 45 C scale units S4 Manufacturer s declared value Class Mass loss (kg/m 2 ) Weathering W1 No performance determined Resistance W2 1.0, no individual value >1.5 W3 Manufacturer s declared value Visual Aspects Appearance No cracking, flaking or delaminating
Masonry Units PROPERTIES BS 6073-1 CRITERIA Dimensional Check Length Height Thickness +3mm - 5mm +3mm - 5mm ±2mm average ±4mm individual Compressive strength a) 7.0N/mm 2 b) 0.9*7.0 + 0.62*S a (N/mm 2 ) Transverse Strength 0.65 N/mm 2 Drying Shrinkage 0.06% a- Standard deviation
Certification at BRE BRE has conducted UKAS-accredited testing on selected samples of glass pozzolan to check CCC s proposed specifications (presentation to follow) BRE has also tested the selected factory products for compliance with appropriate British standards (presentation to follow)
Summary Glass pozzolan testing at the CCC has shown that waste container, flat and lighting glass is pozzolanic Based on extensive testing of waste glass chemistry, contamination and effects on fresh and hardened concrete properties, the CCC has proposed detailed specifications for glass pozzolan for use in concrete The CCC s results have been corroborated by testing in an UKAS laboratory (presentation to follow) Selected ConGlassCrete products that passed 1-year ASR testing at the CCC are undergoing 3 rd party compliance testing as part of the certification processes (presentation to follow).