Coal flyash tested as building block material

Oak Ridge National Laboratory researchers are testing a new lightweight concrete building material that could be used for the walls of homes and businesses.

Researchers at ORNL’s Buildings Technology Center, working with TVA and Babb International of Ringgold, GA, are testing an autoclaved aerated concrete block weighing as little as one-fifth the weight of an ordinary concrete block. This block is composed of 70% recycled flyash produced by TVA’s coal-fired power plants.

Plans call for the flyash block wall to be tested for one year at a ‘Habitat for Humanity’ home to be built in northern Georgia. ORNL researchers hope to install instrumentation while monitoring the energy efficiency and air-tightness of the home. The results will be compared to data obtained from the insulation monitoring of two Habitat homes built more than a year ago in Lenoir City.

Testing is taking place at ORNL’s Buildings Technology Center, a US DOE national user facility that conducts research in improving systems that make up roofs, walls and building foundations, as well as the insulating materials these systems contain.

Jeff Christian, director of ORNL’s Buildings Technology Center, said that preliminary tests in the Buildings Technology Center’s whole-wall hot box indicate that walls manufactured from the material produce a thermal mass effect that can heat a home at night long after the sun has set.

‘The thermal mass benefits of the autoclaved aerated concrete wall can result in a home as energy efficient as a typical home constructed of 2 by 4s in the Knoxville area,’ Christian said.