Certification of Glass for Use in Concrete I Dr Belen Morales

Transcription

1 Certification of Glass for Use in Concrete I Dr Belen Morales Manager ConGlassCrete II Project Centre for Cement and Concrete University of Sheffield

2 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)

3 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

4 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) Plate (R) Windscreen (PC) Car Windows (PC) Blue (R) < Green (R) Amber (R) Cullet (PC) Cullet 1 (PC-washed) Cullet (PC) Cullet (PC) Cullet (PC) Cullet (PC) Cullet (PC) Fluores. tubes (PC) Light bulb (R) Average GGBS < <0.4 <1 <14 PFA MS <0.5 <0.4 <0.5 <0.7 <0.2 <1

5 Experimental Materials 33 Waste Glasses Tested NUMBER TYPE FINENESS RANGE (m 2 /kg) 1-5 Plate (R) Plate (PC) Windscreen and side-rear windows (PC) , 14 Single colour container (R) Mixed colour container (PC) Light bulbs (R) Fluorescent Tubes (PC) R-Rejected by glass Industry PC- Post-consumer

6 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 < a Plate (R) <0.05 < a Windscreen (PC) <0.05 < a b <2 8 Car windows (PC) 0.05 < a b Blue (R) <0.05 < a Green (R) 0.23 <0.05 < a Amber (R) <0.05 < a Cullet (PC) 0.06 < a Cullet (PC) 1.13 < a Cullet (PC) 0.12 < a b - <2 20 Cullet (PC) 0.11 < a b - <2 21 Cullet (PC) 0.14 < a b - <2 22 Cullet (PC) 0.12 < a b - <2 30 Fluores. tubes (PC) <0.05 < Light bulb (R) 0.15 < a to BS 2646 (550ºC, 1h) b to BS (975ºC, 2h)

7 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) h 95.5% Plate (R) h 95.5% Plate (R) h 100.0% Windscreen (PC) % Car windows (PC) h 100.0% Green (R) % Amber (R) % Cullet (PC) h 101.3% Cullet (PC) h 100.0% Cullet (PC) h 100.0% Cullet (PC) h 101.3% Fluor. Tubes (PC) h - Fluor. Tubes (PC) h 97.8% a BS b BS

8 Strength Development I (industrial sub-project) 80 (a) Green Glass Pozzolan 80 (b) Green glass pozzolan and sand Compressive strength (N/mm 2 ) PC Control PC/GP10 PC/GP25 PC/GP Age (days) PC Control PC/GGS 50 PC/GP10/GGS 50 PC/GP25/GGS Age (days)

9 Strength Development II (laboratory mortar test to BS EN 450) Relative strength (%) (a) 28 days of curing Surface area > 300m 2 /kg achieves BS EN 450 strength compliance BS EN 450 minimum relative strength (b) 90 days of curing Surface area > 300m 2 /kg achieves BS EN 450 strength compliance BS EN 450 minimum relative strength Surface area (m 2 /kg) Surface area (m 2 /kg)

10 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 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 % N/R N/R N/R Free CaO, max % 1 N/R N/R Chloride, max % N/R N/R N/R Sulfur trioxide (SO 3 ), max % Loss on ignition, max % 5-7 a Fineness (retained on 45µm sieve) max % 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 N/R Max deviation 5 % Moisture content, max, % N/R Water requirement, max. % of (30% cement replacement) N/R control Initial setting time (30% cement replacement) N/R Not less than cement N/R N/R not requirement a- National basic

11 Proposed Specification for Glass as Concrete Pozzolan PARAMETERS CRITERIA METHODS SiO 2, min % 68 BS Chloride, max % 0.1 BS Loss on ignition, max % 1.5 BS Surface area, min m 2 /kg 300 BS Activity index, min 75% at 28 days 85% at 90 days BS Soundness, max expansion 10mm BS Initial setting time, max 2h more than control BS Lead, max % 0.1 BS 6748 a a-limits of metal release from glassware, glass ceramic and vitreous ware

12 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

13 Grey Blocks PROPERTIES BS CRITERIA Dimensional Check Length Height Thickness +3mm - 5mm +3mm - 5mm ±2mm average ±4mm individual Compressive strength a) 7.0N/mm 2 b) 0.9* *S a (N/mm 2 ) Transverse Strength 0.65 N/mm 2 Drying Shrinkage 0.06% a- Standard deviation

14 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

15 Masonry Units PROPERTIES BS CRITERIA Dimensional Check Length Height Thickness +3mm - 5mm +3mm - 5mm ±2mm average ±4mm individual Compressive strength a) 7.0N/mm 2 b) 0.9* *S a (N/mm 2 ) Transverse Strength 0.65 N/mm 2 Drying Shrinkage 0.06% a- Standard deviation

16 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)

17 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).