Deleterious Materials - Page 19 of the Expert Panel Report On Defective Blocks, which highlights the fact that the cause of the crumbling blocks is not Mica.
The following list describes the most common deleterious materials and their effect on concrete, which include: - 126.96.36.199 Sulfates Interaction between sulfate and cement paste causes the generation of the mineral ettringite. This causes extensive cracking, expansion, loss of bond integrity between the cement paste / aggregate particles and the alteration of the cement paste composition.
In wet / saturated, low temperature conditions Thaumasite replaces the cement paste causing the concrete surface to soften and eventually disintegrate; 188.8.131.52 Sulfides Sulfide minerals, in particular iron sulfides such as pyrite and the much more reactive marcasite or pyrrhotite, can have a considerable effect upon concrete strength. In-situ oxidation, disintegration and dissolution of iron sulfides weakens the aggregate strength. The chemical reaction between oxidising pyrite and calcite causes the formation of secondary gypsum with an associated volume increase (greater than twice the volume of the original iron sulfide mineral). In addition, the oxidation of iron sulfide can produce sulfuric acid, which attacks the cement paste (i.e. Mundic Decay).
What is truly amazing is to find out that the members of the Expert Panel, highly qualified engineers and geologist, were very much aware that the above list of deadly materials could possibly be the cause of the crumbling effect on the building blocks and decided to ignore them completely.
As we now know from the Petrolab analysis of the concrete coring samples, excessive amounts of the above mentioned Reactive Iron Sulphides have been identified in hundreds of cases and are indeed considered the real scientific reason the blocks disintegrated and crumbled and in truth little to do with Mica.
The fact that the Expert Panel, in an attempt to cover their backs, found it necessary to print a disclaimer at the beginning of the report Disclaimer . . . The Expert Panel did not commission or carry out any tests on buildings or building materials itself and was dependent on technical information supplied directly to it by homeowners and concerned parties.
And again on page eleven - It should be noted that it was not in the Panel’s remit to commission testing to verify the cause of the defects claimed in these reports - tells you all you need to know as to what was really going on here.
The decision by the Govt to restrict the Expert Panel to a desk top study and not allow the crumbled block material to go for analysis is the beginning of the planned cover-up. As we see from the report the expert panel fell into line and followed the Govt's restrictive Terms of Reference as did all the rest of those involved in the design of the fraudulent I.S. 465 - all the way to the 90/10 legislation of SI 25 of 2020 and to the present enhanced Remediation of Dwellings Damaged by the use of Defective Concrete Blocks Act 2022.
In Part 4 we will look at the membership of the Technical Committee set up by the NSAI to design I.S. 465 in response to the Expert Panel report.
⏩ Enda Craig is a Donegal resident and community activist.