Self-healing concrete? Small Inclusions Make the Difference, Part 1
Lime “Contaminant” in Roman Concrete is the Key to its Longevity
Sometimes, the omission of one small thing, such as a step in a process or an ingredient in a recipe, can make an end-product less desirable, tasty, effective, or reliable than it could be. Think of leaving the leavening out of a cake or blowing off the stretching before and after a long jog. In the end, you will still have a cake, albeit flat, and you will still have the cardiac benefits of a run, although you will probably be left with sore, tight muscles as a consequence. These are imperfect outcomes.
Small additions can be of great consequence. On January 26, 2023, the MIT News Journal published the results of a fascinating study concerning the longevity of the concrete used in ancient Roman structures such as the still used Roman aqueducts, ports, roads, and buildings including the famous Pantheon. These structures were built around 128 C.E., and for years, scientists, geologists and engineers agreed that the concrete’s durability came from pozzolanic material (originating from volcanic ash) found in the region and incorporated into the concrete mix, and mixing the concrete at high temperatures.
More recently, a much more interesting and astonishing finding has surfaced, thanks to the work of the brilliant MIT scientist, Admir Masic! The ability of this concrete to heal itself from spontaneous fractures is now thought to be due to lime clasts long identified in the building materials, and previously thought to be “contaminants.” The MIT News Journal article, linked above, details this fascinating process and the concrete’s resulting durability. One small thing…not omitted but included…has made all the difference.
What does ancient Rome have to do with our WILDCAT DCP? The engineers in ancient Rome knew to include a step, adding lime clasts to their concrete mix and mixing at high temperature, that would ultimately make all the difference in their end product. Similarly, Fred Triggs P.E., the creator of the WILDCAT, knew that using a polymer slurry in DCP testing would make data accurate and dependable; ultimately, it makes the DCP testing worth doing. Small inclusions for big results in both scenarios.
In our next blog installment, we’ll dive in to more information and instruction on slurry use with the WILDCAT DCP.
