dr andrew dunster, principal consultant bre/file/10.pdf · dr andrew dunster, principal consultant...

Certification of Glass for Use in Concrete II

Dr Andrew Dunster, Principal Consultant BRE

ConGlassCrete – High Value Use of Waste Glass in Concrete Products

Overview of Presentation

• Product certification/pre-certification• Glass as a pozzolan

Test results and limits

• Concrete products containing glassTest results and limits

• Getting full approval


BRE Certification

BRE Certification - who are they?• a wholly owned subsidiary of the Foundation

for the Built Environment (FBE)• a sister company to BRE• specialists in certifying products and services

to the building and construction industries


Certification

• Certification is third party confirmation that products, services, systems and personnel meet and continue to meet certain standards and specifications

• The technical requirements are peer reviewed by an independent panel of experts


Pre-certification

• Certification normally covers a material or product that is being produced (includes production control etc)

• Alternative: pre-certification testing report stating that a material should be produced to particular parameters (chemical composition, strength fineness etc)


Objectives

The performance of the pozzolana/products and the limits on properties assessed by BRE using UKAS facilities:• Validate test data from CCC (pozzolana)

• Generate new test data (concrete products)

• Assess limits for certification.

• Check data for conformity with limits


Glass as a pozzolana

Validation tests


Sources of glass pozzolana

1- glass from bottle banks 2- glass bottles from pubs and clubs 3- glass cullet-reject from manufacturers 4- flat glass 5- end of life vehicle glass 6- fluorescent tubes


Key properties of glass pozzolana (1)

Key properties (based on PrEN450):

•Total SiO2 (min %)

•Chloride (max %)

•Loss on ignition (max %)

•Fineness based on surface area (min)

•Strength Activity index (min, % control)

•Soundness (max expansion)


Key properties of glass pozzolana (2)

Key properties (based on PrEN450):

•Particle density (min kg.m-3)

•Moisture content (max, %)

•Water requirement (max, % control)

•Initial setting time

•Lead and other metals levels (max)


Six samples of glass pozzolana selected for validation testing

•Fluorescent tubes (post consumer unwashed)

•Container (green, rejected)

•Container (amber rejected)

•Container (post consumer unwashed)

•Plate (rejected)

•Windscreens (post consumer, unwashed)


Results: Soundness and setting time

170180165190180190160Initial setting time (min)

1.01.00.00.500.01.0Soundness,

max expansion

(mm)

Windscreens (unw)

PlateCont (unw)

Amber cont

Green cont

f/tubes (unw)

Ground glass sourcePC Control


Results: Strength activity index 28 days

0

20

40

60

80

100

120

PC Control fluor tubesunwashed

Green container Amber container Containerunwashed

Plate Windscreensunwashed

Stre

ngth

act

ivity

inde

x (%

)

UoS 28 days

UKAS 28 days


Results: Strength activity index 90 days

0

20

40

60

80

100

120

PC Control fluor tubesunwashed

Green container Amber container Containerunwashed

Plate Windscreensunwashed

Stre

ngth

act

ivity

inde

x (%

)

UoS 90 days

UKAS 90 days


Results: Specific surface area of ground glass pozzolana (Blaine

method)

050

100150200250300350400450500550600650700750800850900950

fluor tubesunwashed

Green container Amber container Container unwashed Plate Windscreensunwashed

Spec

ific

surf

ace

area

(M2 /k

g)


Key limits for ground glass as a pozzolana

(30% cement replacement)

10 mm[2]BS EN196-3Soundness, maximum

expansion

(25% cement replacement) at 28 days

75% -5%at 90 days 85%-5%[1]

BS EN 196-1Strength Activity index, minimum. percentage of control

300 m2/kg minimum BS EN 196-6Fineness based on surface area minimum

1.5%Loss on ignition, max %0.1%EN196-21Chloride, max %

68% minimumBS196-2Total SiO2, min %-EN197-1Reactive SiO2 min %

LimitsTest methodProperty

[1] Limit values for single results are 70% and 80% respectively[2] Current limit 50% in EN450. The limit has been reduced to 30% and this is out for comment at present


Key limits for ground glass as a pozzolana

Maximum 0.1% PbOMaximum 1 ppm CdO

XRF or solution methods

Lead levels (and other metals) maximum

< 120 minutes more than cement (at 30% replacement) and not less

than cement aloneEN 196-3Initial setting time

Not more than cement + 3%BS 3892 EWater requirement, max. percentage of control

-BS 3892 CMoisture content, max, %-EN196-6Particle density, min kg.m-3

LimitsTest methodProperty


Frequency of testing for ground glass pozzolana

• Difficult to be definitive about the level of factory production control required

• Most frequent tests likely to be required are: Fineness (at least once a day on a routine basis) Soundness Strength activity Index Setting time

• Tests for silica, chloride, lead and other metals are likely to be required less frequently than for the parameter listed above.


Conclusion

• Ground glass pozzolana judged “fit for purpose” and suitable for use as a pozzolanic replacement to cement.

• Levels of replacement up to 25 % (by weight of cementitious material) likely to be achievable.

• Durability not covered by the pre-certification assessment. Further work needed to extend the range of claims made for the material


Concrete Products

Pre-certification testing


Concrete Products

Glass pozzolanaThree test mixes and a standard or control mixPaving blocks

WPC, blue glass aggregate, metakaolinOne test mixDecorative masonry

blocks

Green glass pozzolana, aggregate from post consumer cullet from pub and

pub collection

Three test mixes and one control mixMasonry blocks

Glass contentMixesProduct


Grey Masonry Blocks(Stowell Concrete Ltd)


Paving Blocks(Aggregate Industries UK)


Masonry Units(CRH Forticrete)


Essential characteristics for Grey Blocks: BS 6073-1:1981

≤ 0.09%Drying Shrinkage

a) ≥ 7.0 N/mm2

b) ≥ 0.9*7.0 + 0.62*S (N/mm2), S is the standard deviation for the sample

Compressive Strength

Maximum deviation:Length: +3mm -5mmHeight: +3mm -5mm

Thickness: +2mm -2mm average+4mm -4mm individual

Dimensional Check

CriteriaProperties


Essential characteristics for Architectural Masonry Units: BS

6073-1:1981

?Freezing-thawing

≤ 0.09%Drying Shrinkage

≥ 0.65 N/mm2Transverse Strength

a) ≥ 7.0 N/mm2

b) ≥ 0.9*7.0 + 0.62*S (N/mm2), S is the standard deviation for the sample

Compressive Strength

Maximum deviation:Length: +3mm -5mmHeight: +3mm -5mm

Thickness: +2mm -2mm average+4mm -4mm individual

Dimensional Check

CriteriaProperties


Essential characteristics for Paving Blocks: BS 6717:2001, BS

EN 1338:2003

Manufacturer’s declared valueS4≥45S3≥35S2

No performance determinedS1Mean valueClass

Slip/Skid Resistance

23mmA2No performance determinedA1

Degree of abrasionClassAbrasion

Resistance

≥ 3.9 N/mm2 average≥ 2.9 N/mm2 individual

≥ 250 N/m failure load, individual

Tensile Splitting Strength

Thickness <100mm: Length & width ± 2m, thickness ± 3mmThickness ≥100mm: Length & width ± 3m, thickness ± 4mm

Shape and Dimensions

CriteriaProperties


Essential characteristics for Paving Blocks: BS 6717:2001, BS

EN 1338:2003 (continued)

No cracking, flaking or delaminatingAppearance Visual Aspects

Manufacturer’s declared valueW3≤1.0, no individual value >1.5W2No performance determinedW1

Mass loss after testmean value (kg/mm2)Class

Weathering Resistance

CriteriaProperties


Conclusion

Concrete products tested complied with strength and drying shrinkage requirements of appropriate standards (BS 6073-1:1981, BS 6717:2001)

Concrete products containing glass had same performance classification as control mix (without glass)


Full Approval: requirements include the following

• Manufacturers to independently submit formal application to BRE Certification. BRE Certification fees and timescale will be included in the proposal.

• Assessment of factory production control including initial visit to manufacturing location to check material sources, processing, traceability, compliance with limits etc

• Testing as required by relevant product standards/ Building Regulations

• Assessment of the product life expectancy (durability)

Preparation of draft certificate and circulation to BRE Certification Construction Board


Thank you for your attention

• www.brecertification.co.uk

• www.bre.co.uk

dr andrew dunster, principal consultant bre/file/10.pdf · dr andrew dunster, principal consultant...

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