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MAT-5 CONCRETE

Technical Clarification

Gabions as a non-concrete application

Technical Clarification Number
MAT5-T-OB1-1206

Guidance
2016-01-28

For the additional 3rd point of credit Mat-5 as it relates to “non-concrete applications (e.g. stone sub-soil drains, road layerworks and backfill, etc.)”,​ the GBCSA confirm that gabions can be excluded as they are deemed to not be aggregates for the purposes of this credit.



 

 

Technical Clarification

Definition of non-structural in-situ concrete

Erratum Number
MAT5-T-OB1-918

Guidance
2015-07-17

Under MAT 5, to achieve the additional 3rd point:

 1) 10% of all aggregate used for structural (concrete) purposes is to be recycled aggregate (equivalent to Class 1 RCA as per Australian standard HB155-2002) or slag aggregate; AND

2) No virgin aggregates are used in non-structural in-situ concrete applications (e.g. (concrete) footpaths, (concrete) curbs, (concrete) backfilling to service tranches, etc.) and non-concrete applications (e.g. stone sub-soil drains, road layerworks and backfill, etc.)

 The definition of non-structural in-situ concrete is, according to GBCSA, ‘not forming part of any load bearing or engineered element that is poured on site’. And similarly the definition of structural concrete, according to the GBCSA, is ‘forming part of any load bearing or engineered element’. A structural engineer can determine on a project how this definition applies to specific applications.

 

Erratum

Virgin aggregate in pre-cast non-structural items.

Erratum Number
MAT5-E-OB1-721

Guidance
2013-08-20

On page 235 of the Green Star SA – Office v1 Technical Manual, under ‘Credit Criteria’, additional point, change the last bullet point to read “No virgin aggregates are used in non-structural concrete uses (e.g. footpaths, backfilling to service trenches). Note that this requirement applies to non-structural concrete aggregate applied on site and not to pre-cast non-structural concrete uses.”

 

Credit Interpretation Request

Proprietary mixes

Credit Interpretation Request Number
MAT5-C-OB1-683

Ruling
2013-06-13

The Project team’s proposal to demonstrate compliance by complying with the 15% threshold of Portland cement reduction for stressed concrete, and an average cement reduction of 30% across pre-cast and in-situ mixes is approved for the first point of the credit only.

Alternatively, please note that the GBCSA also provide the following guidance to the project team with respect to proprietary concrete mixes:

Where suppliers are not able to divulge the exact composition and proportions of components of their proprietary concrete mixes, the project team may submit a statement of confirmation from the supplier clearly stating the resulting reduction of Portland cement content in the mix compared to a base case scenario with the same structural and functional requirements, and applying to the same location and conditions.

Note that concrete technologist report is thus not required to state the proportions of components for these proprietary mixes. However, the report must show how the cement reduction achieved by these proprietary mixes along with the cement reduction calculated for all other mixes is taken into account in confirming compliance with the credit criteria

 

Credit Interpretation Request

Approval of published mix design ratios

Credit Interpretation Request Number
MAT5-T-OB1-0660

Ruling
2013-03-13

It is left up to the Concrete Technologist’s professional discretion to put forward a reference case that has the same structural and functional requirements, and apply to the same location and season.

Should the Concrete Technologist believe that the mix design ratios published by the Cement and Concrete Institute (CNCI) or any other reputable source/authority is an acceptable reference to calculate the reference case mix design for their specific project, this will be deemed acceptable. It is neither the GBCSA’s nor Assessors’ prerogative to question this.

The determined reference case must be stated in the Concrete Technologist report as per the documentation requirements stipulated in the Green Star SA Office v1 Technical Manual.

 

Technical Clarification

Minor ancillary concrete applications

Technical Clarification Number
MAT5-T-OB1-646

Guidance
2013-02-22

The GBCSA acknowledge that for small, inconsequential concrete uses, the sourcing of mix designs for these applications may be unnecessarily onerous given their impact in terms of credit compliance. As such, please note that it is acceptable for marginal and ancillary applications to be included in calculations for this credit as a conservative generic mix rather than having to source a mix design for each and every low volume concrete component. For example, the project team could structure the calculations for the Mat-5 credit so that items such as kerbs, pipes, lintels, paving blocks, sills and similar items are included as a conservative generic 100% OPC mix. No further documentation would be required for the proposed approach, but the project team needs to provide calculations for the specific project to demonstrate that these applications have been included.”

In addition, please note that it is not the intent of the Credit Criteria to encompass minor miscellaneous concrete applications such as small statues, benches, landscaping steps, concrete filled manhole covers, etc. Although noted as concrete applications within buildings, these are excluded from the scope of the Mat-5 credit due to the general quantity of concrete represented and the practicalities of quantification. It is also noted that in some projects, the credit criteria benchmarks may be comfortably achieved for all major concrete applications and minor applications such as paving, kerbs, channels, gutters, lintels and stormwater piping will represent a small fraction of the project’s concrete use and as such will not affect compliance. In such cases the project team may justify this within the ‘Concrete Technologist / Structural Engineer’s Report’ with a simple calculation using conservative estimates of quantities as well as a conservative 100% OPC concrete mix. This conservative calculation must clearly show that these items combined do not significantly impact compliance with the criteria benchmarks and as such can be regarded as negligible.

 

Credit Interpretation Request

Minor ancillary concrete applications

Credit Interpretation Request Number
MAT5-C-OB1-647

Ruling
2013-02-22

The proposal to alter the credit criteria wording from “all concrete mixes” to “95% (volume) of concrete mixes”, as well as provide a list of concrete uses that make up that 95%, is denied.

The Technical Advisory Group and GBCSA do not necessarily disagree that the proposed approach would for the most part achieve the same aim as the current credit, and in fact recommend that this approach is reviewed for inclusion in Green Star SA – Office v2 of the rating tool. However it is felt that within version 1 of the tool, the following clarifications would address the main issues raised (listed below) adequately until the credit is reviewed in entirety for Green Star SA – Office v2.

1) The burden of sourcing mix designs for small, inconsequential concrete uses:
See TC MAT5-T-OB1-646

2) The burden of sourcing mix designs for small, inconsequential concrete uses:
See TC MAT5-T-OB1-646

 

Erratum

Green Star SA – Office v1 Technical Manual: Page 237

Erratum Number
MAT5-E-OB1-0631

Guidance
2013-02-07

Confirmation from the Suppliers first bullet point delete: “and aggregate (both recycled and non-recycled) supplied to site.”

Add a new bullet point after the first to read: “- Where the additional point is claimed, confirmation of the quantities of aggregate (both recycled and non-recycled) supplied to site.”

 

Technical Clarification

Technologist Report, quantity of cement and additional point

Technical Clarification Number
MAT5-T-OB1-0631

Guidance
2013-02-07

To demonstrate compliance with the credit criteria, within the Concrete Technologist Report, project teams need not provide the full breakdown of composition and proportions of components for each mix.

In order to demonstrate compliance with the credit criteria, only the quantity of cement per cubic meter of mix and total cement for each mix need be presented against a reference case for the first 2 points.

For projects pursuing the additional (aggregate) point: only the total mass of aggregates per cubic meter, mass of recycled aggregates per cubic meter and total mass of aggregates need be presented in order to demonstrated that concrete mixes are compliant. Non-structural aggregates used (for example as fill, sub-grades and building base course) must clearly be accounted for separately and demonstrate that 100% of the aggregate was not from virgin sources.

 

Credit Interpretation Request

Alternative percentage reduction metrics

Credit Interpretation Request Number
MAT5-C-OB1-0355

Ruling
2012-01-27

For the purpose of compliance with the credit criteria, it is acceptable to demonstrate that the project has reduced the absolute quantity of Portland cement by a minimum percentage as an average across all concrete mixes (in situ, precast and stressed). One point shall be awarded for 30% reduction OR two points awarded for 40% reduction.

Where the average percentage reduction of Portland cement across all concrete uses is demonstrated, individual evidence of Portland cement reductions for in-situ, pre-cast or stressed concrete types is not required.

Credit Criteria of the additional point remains unchanged.

 

Technical Clarification

Portland cement content in concrete reference cases

Technical Clarification Number
MAT5-T-OB1-356

Guidance
2012-01-27

A concrete reference case is typically provided in Mat-5 Concrete credit submissions to demonstrate the percentage of total Portland cement replaced in all concrete uses by supplementary cementitious materials (SCM).

To ensure consistency in Green Star project submissions and the assessments of this credit, the GBCSA deems it acceptable for project teams to present concrete reference cases that assume the use of baseline concrete mixes with 100% Portland cement content (i.e. use no SCM).

Projects may still provide concrete reference cases with more realistic mix designs that do contain some percentage of SCM, which is common industry practice, however this is not mandatory.

 

Technical Clarification

Percentage reduction metrics

Technical Clarification Number
MAT5-T-OB1-0329

Guidance
2011-10-13

For the purposes of demonstrating the percentage reduction of Portland cement from the reference case, it is acceptable that calculations are presented in volume or mass.

 

Erratum

Green Star SA - Office v1 Technical Manual: Page 235

Erratum Number
MAT5-E-OB1-0277

Guidance
2011-08-08

Credit Criteria, for the third bullet point under the 'Additional point', change "No natural aggregates are used in non-structural uses…" to read "No virgin aggregates are used in non-structural concrete uses…"

 

Erratum

Green Star SA - Office v1 Technical Manual: Page 236

Erratum Number
MAT5-E-OB1-0194

Guidance
2011-01-06

Documentation Requirements, documentation table, As Built section, change "Confirmation(s) form supplier(s)" to "Confirmation(s) from supplier(s)".

 

Erratum

Green Star SA - Office v1 Technical Manual: Page 236

Erratum Number
MAT5-E-OB1-0195

Guidance
2011-01-06

Documentation Requirements, documentation table, Design section, change the first and fourth bullet point from "Concrete Technologist report" to read "Concrete Technologist / Structural Engineer's report".

AND

Documentation Requirements, documentation table, As Built section, change the first and fifth bullet point from "Concrete Technologist report" to read "Concrete Technologist / Structural Engineer's report".

AND

Documentation Requirements, description of documentation, change the bold heading "Concrete Technologist report" to read "Concrete Technologist / Structural Engineer's report".

 

Technical Clarification

Alternative documentation requirements - Concrete Technologist report

Technical Clarification Number
MAT5-T-OB1-0111

Guidance
2010-11-02

The ‘Concrete Technologist report’ may be substituted with a report from either the Structural Engineer or Civil Engineer where the report demonstrates the exact same requirements as outlined in the Technical Manual. This report must reference Concrete Technologist report(s) and/or product manufacturer data sheet(s) and/or statement(s) of confirmation from product manufacturers to substantiate compliance with the credit criteria where applicable.

 

 

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