Mundic Testing here we come!

We are now offering our clients a new service “Mundic Testing”.

Here is an introduction to Mundic Testing and why it may be relevant to you.

Many properties in the South West of England are constructed from concrete blocks laid onto mass concrete foundations. The main reason for the use of concrete blocks in this area is the non-availability of suitable raw materials to form and mould conventional red clay bricks.

Blocks were produced from waste rock worked from mining, quarrying and free supplies of beach gravel. The mine waste rock was of a coarse aggregate with fine mix aggregates produced from beach sand, china clay waste or mine processing residue.

The production of the blocks using these materials took place from the turn of the twentieth century until the 1950s when mass production of widespread concrete blocks became common. This did not totally eradicate the use of local materials in block and foundation construction until the early 1960s.

Problems

Some of these local materials used as aggregates in concrete construction can cause deterioration and mechanical weakening of the building form. Lack of cement can cause deterioration too.

Types

1. Sulphide Minerals

often found in mine or quarried rock. These can oxidise under damp atmospheric conditions with the production of sulphuric acid. This attacks the cement causing weakness and expansion – commonly called ‘Mundic Decay’.

2. Fine Grained Rocks

these are formed by sediments laid down on the floor of oceans and can be quite soft. They can change volume and delaminate under attack from moisture fracturing the cement of the concrete. This effect is called ‘Killas’.

3. Furnace Residue

Clinker, Coking Breeze and Slag from metal smelters, gasworks and laundries. If the coal has not been adequately burnt it can expand when wet causing cracking.

4. Reactive Silica

such as flint found in beach gravel generally found in mass concrete.

Testing for mundic block

To establish the condition of the building materials within the dwelling suitable testing is required.

The present screening test was developed by the Royal Institution of Chartered Surveyors with input by the Building Research Establishment in 1994 and revised in 1997, and identifies major problems of concrete degrading.  Supplementary stage three expansion testing was added in 2005.

The test consists of a two-stage analysis and a stage three performance assessment.

Preliminary Screening Test

The screening test involves taking a number of 50 mm diameter drill holes where a “core” is taken from the external walls, samples of foundations and, where accessible, internal walls and chimney.

These are examined in a laboratory and determine the category as below:-

  • Class A – Sound concrete satisfactory condition.
  • Class A/B – Concrete considered sound subject to adequate protection and maintenance.
  • Class B – Concrete contains more than 30% possible problem aggregates although appearing sound could cause potential problems.
  • Class C – Those are found to be clearly unsound from examination.

The examination will identify that the concrete is composed of suitable materials and hence Class A.

In dubious cases, after the Preliminary Stage 1 when concrete cannot be placed into ‘A’ or ‘C’, it is recommended that further testing be carried out.

Stage 2

The examination will identify and classify results that cannot be defined by the above test and determine Classes ‘A/B’ and ‘B’.

Stage 3

The examination will assess the performance of the aggregate material with the core samples previously taken.

It can be applied to ‘Class B’ material following the stage two investigation when, in the opinion of the surveyor and the petrographer, they are satisfied that the property’s structural condition and examined core material do not indicate visible deterioration.

Tests are carried out in laboratory conditions to simulate extreme weathering.

Current statistics indicate that 75% of properties prove successful when subjected to this examination.

Successful results are reclassified as ‘Class A/B’.

Results

Examination and classification results in that:-

  • Class A and A/B  sound and acceptable.
  • Class B  sound now but containing too much deteriorating material to be regarded  as stable.
  • Class C  unsound and repair needed.

A large number of properties have been examined and the results indicate some 80% have passed in Class A at the preliminary screening stage, about 5% have gone to Class C.

The remaining 15% have undergone Stage Two examination and many have been regraded Class A or A/B.

Class C materials it is recommended that examination be made by a Structural or Civil Engineer.

Information gathered from: http://www.cornwall.gov.uk/default.aspx?page=22645

About

Having served 16 years in the army Colin re-educated during the early 1990’s including two years at the Camborne School of Mines reading Mineral Surveying and Resource Management achieving a first class Diploma (Dip CSM). This allowed direct entry to the second year at The University of the West of England, Bristol reading Valuation and Estate Management. Training and experience was gained with Exeter City Council Estates Department and Sheperds Chartered Surveyors qualifying as a Member of the Royal Institution of Chartered Surveyors in June 2003. Colin set-up the company in May 2009 and covers the complete range of services.

31 Responses to “Mundic Testing here we come!”

  • nice post. thanks.

  • Took me time to read all the comments, but I really enjoyed the article. It proved to be Very helpful to me and I am sure to all the commenters here! It’s always nice when you can not only be informed, but also entertained!

    – Josh

  • Took me time to read the whole article, the article is great but the comments bring more brainstorm ideas, thanks.

    – Johnson

  • ha, I am going to experiment my thought, your post give me some good ideas, it’s really amazing, thanks.

    – Norman

  • the precious information you presented do help the research for our group, appreaciate that.

    – Lucas

  • This is very interesting. I actually enjoy your writing style and your word choice more than anything Smile

  • Your articles are very inspiring indeed. I keep coming back! There are so many things I agree on. I hope we can exhange ideas in the future.

  • Thank you for this interesting contribution.

  • I searched many sites and here i found what i was looking for, thanks for valuable post

  • Thank you for this post. Thats all I can say. You most definitely have made this blog into something speciel. You clearly know what you are doing, youve covered so many corners.see you

  • This post has been extremely helpful to me. Thank you.

  • Thanks for taking the time to talk about this, I feel fervently about this and I take pleasure in learning about this topic. Please, as you gain information, please update this blog with more information. I have found it very useful.

  • hello there beautiful site and layout. I am hoping I’m not pestering you I just sought to inquire precisely what wordpress plugin you have to show the most recent feedback on your blog? I want to do something like that for my free ipad page yet I can’t get the plugin or widget for it. Thanks a lot for your time 🙂

  • Hello

    I do all the feedback updates manually by hand. I’m not sure if there is a widget out there to do this for me (and for you) but if you come across one please do let me know as it would be very useful.

    Thank you.x

  • I am usually to running a blog and i really recognize your content. The article has actually peaks my interest. I’m going to bookmark your site and keep checking for brand spanking new information.

  • I feel like you could probably teach a class on how to make a great blog. This is fantastic! I have to say, what really got me was your design. You certainly know how to make your blog more than just a rant about an issue. Youve made it possible for people to connect. Good for you, because not that many people know what theyre doing.

  • Thanks for taking the time to talk about this, I feel fervently about this and I take pleasure in learning about this topic. Please, as you gain information, please update this blog with more information. I have found it very useful. There have to be charging stations everywhere.

  • You sure do know what youre talking about. Man, this blog is just great! I cant wait to read more of what youve got to say. Im really happy that I came across this when I did because I was really starting to get bored with the whole blogging scene. Youve turned me around, man!

  • Wow! Thank you! I constantly needed to write on my blog something like that. Can I include a portion of your post to my website?

  • Dear admin, thanks for providing this blog post. I found it great. Take care,

  • There is obviously a lot to know about this. Thank you.

  • Hey I just wanted to let you know, I actually like the piece of writing on your website. But I am employing Firefox on a machine running version 9.10 of Crashbang Ubuntu and the look and feel aren’t quite correct. Not a big deal, I can still fundamentally read the articles and look for for info, but just wanted to inform you about that. The navigation bar is kind of tough to use with the config I’m running. Keep up the good work!

  • great article very informative will be back again to visit soon

  • You gave tremendous positive points there. I did a search on the topic and found most peoples will agree with your blog.

  • I was suggested this blog by my cousin. I’m not sure whether this post is written by him as nobody else know such detailed about my problem. You’re incredible! Thanks!

  • Thanks for publishing about this. There’s a heap of great tech info on the internet. You’ve got a lot of that info here on your website. I’m impressed – I try to keep a couple blogs fairly ongoing, but it’s a struggle sometimes. You’ve done a big job with this one. How do you do it?

  • thanks for this awesome text and description of existing question. You’ve made it out better than any discussion I’ve seen. Also thx for citing my classwork on it. Your’s takes it better.

  • Great article. Waiting for more.

  • Thanks for writing about this. There’s a mass of important tech info on the internet. You’ve got a lot of that info here on your web site. I’m impressed – I try to keep a couple blogs fairly on-going, but it’s a struggle sometimes. You’ve done a big job with this one. How do you do it?

  • You got fantastic nice ideas there. I made a research on the topic and got most peoples will agree with your blog.

    Your email is never shared.
    Required fields are marked *




    CommentLuv badge