MIT researchers are testing new concrete mixes

Dive Brief:

MIT researchers are exploring concrete at the atomic level to improve its durability and environmental impact in full-scale use, according to the university.
How the atoms making up concrete arrange themselves indicates the ways in which the material can be strengthened by additives, such as slag and volcanic ash.
The researchers are developing a computer model that can be used to gauge the durability of concrete made using other additives, particularly those that are locally sourced, in a way that makes them transferrable to real-world material selection processes.

Dive Insight:

Concrete is ubiquitous in the built environment. As such, many in the industry have long sought to reduce its environmental impact. Portland cement, which is mixed with water, sand and aggregate to form concrete, is of particular focus due to the amount of CO2 released during its production.

In response, some companies have found ways to capture the excess energy created when cement is made and use it to power equipment, Construction Dive reported last year. Others are developing concrete that can offset its own CO2 emissions from production by absorbing greenhouse gasses once in use.

Replacing some of the limestone used in typical cement mixes with supplementary cementitious materials, including fly ash and slag, has also gained traction. Many researchers, too, are looking to the Ancient Romans for the secrete sauce — or rather, additive — that has allowed their concrete structures to stand for centuries.

While new concrete mixes promise to be a greener alternative to existing options, how they'd hold up in the field has yet to be determined and is one factor limiting their use. The MIT researchers’ computer model will offer insight into performance and longevity for concrete mixes using alternative additives.

Meanwhile, other groups are looking to balance concrete’s environmental performance with additional features, such as the ability to resist high heat, thus lengthening its lifecycle. Concrete that can diagnose and close its own cracks, as well as fracture less often, is also being explored. Those self-healing products also call on materials like fly ash and cellulose.