In the context of “building technology”… | bonder component in cement based composite materials | portland cement | roman cement | geopolymer concrete | construction technology |
Making concrete better
The best traditional Portland based concretes have median lifetimes on the order of decades - and this is usually with significant overhauls and regular maintenance with modern epoxy fillers. Nothing built today will last for the ages. Yet over two thousand years ago the ancient Romans managed to create a concrete mix that has stood the test of time. The Pantheon, originally built as a temple to the Gods, has an unreinforced concrete dome which spans 142 feet and has lasted for over 1800 years. Similarly, concrete Roman harbor structures exist which have been submerged in seawater for over 2000 years and are actually stronger now than when they were first constructed. How is this possible? Recent research at UC Berkeley in conjunction with Lawrence Livermore National Laboratories has shown using nuclear imaging techniques that Roman cement contains an extremely rare mineral called Al-tobermorite. This mineral forms when the cement is exposed to seawater and active ion exchange takes place. The precise reasons why this occurs are complex but stem ultimately from the volcanic pozzolanic material used as part of the mix design. Tobermorite forms fine reinforcing mineral threads which continue to grow and strengthen the cement as it ages, and even “heal” the cement across micro-fractures.
Our group is currently handling, investigating, and testing, a list of about 200 materials among fiber, filler and bonder components in the development pipeline…