Non Shrink Grout

Have you ever wondered how non shrink grout started? I have been looking for a link to a site that would explain it in detail and found one that does give a brief history of it. As I understood it previously, non shrink grouts started as sand, cement and water. Very little water was used at first to prevent the shrinking and it was dry packed. When shrinking started to become a bigger issue as less skilled people were placing it, then installers would add iron aggregate to the mixture. Iron would actually expand, thus reducing the shrinkage, yet also decreasing the strength. Chemicals were later introduced to replace the iron aggregate. Some were gaseous and others had chemical reactions with the cement. The metallic non shrink grout is still important in some parts of grouting. I am told that the metallic grout does better in some machinery when there is vibration and heat. The metallic strands help absorb the vibration better and reduce the powdering that you may get with regular non shrink grouts. In a higher heat environment it will not soften like an epoxy grout which is very good in a vibration load.

The link is below and it is by Philip Smith,P.E., FACI, ASTM L&M Technical Director Resident Engineer.

http://www.lmcc.com/news/0401/0401-3.asp

The history of non shrink grout is interesting because it is one of the products I sell and I believe that I should know what I am selling.