In March of this year the NSAI published the revised draft of S.R. 21. The Standard Recommendation’s full title is,
S.R.21: Guidance on the use of I.S. EN 13242:2013 – Aggregates for unbound and hydraulically bound materials for use in civil engineering work and road construction.
Annex E deals specifically with aggregates for use under (and adjacent to) concrete floors and footpaths.
We are happy to confirm that all relevant Roadstone Ltd locations have been inspected and tested and found to be in full compliance with S.R 21, and all other S.R’s such as
S.R 16 Aggregates for concrete
S.R 17 Aggregates for Bituminous Mixtures and Surface Treatments
S.R 18 Aggregates for Mortar
In 2007, Annex E was added to SR21 in response to concerns about pyritic materials having entered the supply chain from a small limited number of suppliers and resulting in structural damage to a significant number of houses and buildings in the Greater Dublin region. This further revision is substantially on foot of the Pyrite Panel Report 2012 issued by the Department of the Environment, Community and Local Government following an enquiry into the matter.
Annex E Proposed Specifications
1. Material Properties :
(a) Grading, material now to be a continuously graded 0/31.5 mm as per Table E.2 of S.R 21 Annex E.
LA value now required to be a maximum of LA30
Mudrock content of the material shall not exceed 10%
Magnesium Sulphate Soundness value shall comply with MS25
(c) Chemical Requirements:
If <0.1% no Petrography necessary
If between 0.1% and 1% Petrography necessary
If Pyrrhotite present 0.4% Total Sulphur max
If Total Sulphur is > 1% material is unsuitable.
2. Geological and Petrographic Assessment :
More explicit guidance is given on the geological and petrographic assessment to limit the risk of swelling due to the presence of a reactive form of pyrite.
3. Factory Production Control :
Previous specifications generally called for chemical and physical testing of materials on a yearly or bi-yearly basis. This has been increased to the levels contained in Table E.1.
The main changes are:
% Crushed Particles (Gravel only): Monthly
Water Absorption: 2/Year
Total Sulphur: Quarterly
Acid Soluble Sulphate: Quarterly
Geological Description Quarterly
Please note that these test frequencies only apply during times of production. A period of production is defined as a full week, month or year.
These test frequencies may be reviewed based on the advice of a Professional Geologist.
4. System of Attestation and Verification :
The system of attestation and verification of performance has changed from System 4 (self-certification) to System 2+ (independent certification) for this particular end use aggregate. There is an 18 month lead in time to allow certain producers to ensure all Quality Management Systems are in place prior to external audit.
5. Documentation :
The full title, “Granular Fill to Annex E of S.R. 21”, of this special end use aggregate should be clearly stated on the Declaration of Performance, and other documentation including the delivery ticket.
6. Future Proposal :
NSAI Aggregates Panel is now tasked with generating a Code of Practice for the use of hardcore which will include supply chain control arrangements.
Roadstone Ltd have a long and successful history of supplying a wide range of building materials to the Irish construction industry with no issues relating to pyritic heave or swelling.