Mix design and weather durability evaluation of low-density concretes

Abstract

A large portion of the fatal accidents on the Interstate Highway System and freeways are attributed to vehicles colliding with stationary, unmovable objects along the roadside. One attempt to reduce this large number of fatalities has been to install impact attenuators around the stationary objects to absorb the energy of impact. One type of material suggested for use in constructing impact attenuators has been low-density, high energy absorbing concrete. Because impact attenuators constructed from low-density concretes would be exposed to the effects of weather, the low-density. concretes must possess high resistance to the effects of a freezing and thawing environment. This study investigated the actual effects of a freezing and thawing condition in the laboratory on several low-density concretes. The low density concretes tested for freeze-thaw effects in this study were perlite concrete, vermiculite concrete, foam concrete, and polystyrene concrete. Mix designs were made and mix design procedures were established along with mixing and placing techniques for these low-density concretes.