Virtual Cement and Concrete Testing Laboratory for Quality Testing and Sustainability of Concrete

Jeffrey W. Bullard is a Materials Research Engineer in the Materials and Construction Research Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD. He received his B.S. in Ceramic Engineering from the University of Missouri-Rolla and his M.S. and Ph.D. in Materials Science and Engineering from the University of California, Berkeley. He is a member of the American Ceramic Society. His research interests include computational modeling of microstructure development in concrete binders. ACI member Paul E. Stutzman is a Physical Scientist in the Materials and Construction Research Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD. He received his A.B. in Geology from Hanover College and his M.S. in Geology from Southern Illinois University at Carbondale in 1983. His primary research interests include characterization of concrete materials using quantitative X-ray diffraction methods and scanning electron microscopic imaging. Luis M. Ordoñez Belloc is the Coordinator of the Hydraulic Binder Area of the Materials Research Technical Unit at AIDICO-Construction Technology Institute, Valencia, Spain. He received his Ph.D. in Chemistry from the Universidad Politecnica de Valencia, Spain in 2007. His research interests include application of pozzolanic materials in concrete binders and the use of computer modeling in development and improvement of cement and concrete sustainability. ACI Fellow Edward J. Garboczi is the leader of the Inorganic Materials Group in the Materials and Construction Research Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD. He received his B.S., M.S., and Ph.D. in Physics from Michigan State University. He is a member of ACI Committee 236 (Materials Science). His research interests include X-ray computed tomography of random materials, three-dimensional particle shape analysis for cement, sand, gravel, and other particulate materials, and three-dimensional computer models of the microstructure and performance of random materials. ACI Member Dale P. Bentz is a Chemical Engineer in the Materials and Construction Research Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD. He received his B.S. in Chemical Engineering from the University of Maryland and his M.S. in Computer and Information Science from Hood College. He is a member of ACI Committees 231 (Early Age), 236 (Materials Science), and 308 (Curing). His research interests include experimental and computer modeling studies of the microstructure and performance of materials. INTRODUCTION Design, optimization, and quality testing of concrete typically are accomplished by intensive physical testing procedures that consume large amounts of labor and materials. This task is becoming increasingly difficult as requirements for sustainability and performance begin to necessitate the use of blended cements and chemical admixture cocktails that may have significant interactions affecting durability and service life. As a result of this complexity, the performance of concrete over its intended service life is difficult to predict without extensive physical testing, since simple empirical relations cannot be universally applied with confidence. A promising alternative is to use scientifically based computer models to guide testing and development efforts. Properly validated computer models can supplant much of the current empirical design and testing procedures with computer simulations that are relatively quick and inexpensive. This paper describes an integrated package of computermodeling software, called the Virtual Cement and Concrete Testing Laboratory (VCCTL), the goal of which is to enable a rapid exploration of concrete design space at significantly reduced cost. This software has been developed for the last eight years through a consortium led by the National Institute of Standards and Technology (NIST) and with a membership that has included cement manufacturers, chemical admixture suppliers, aggregate suppliers, and industry associations. The computer models in VCCTL continue to be refined to include a wider range of materials and curing conditions. Nevertheless, the models—and the user interface that ties them together—have advanced to a point where they can provide immediate benefits to industry in a number of ways. Features of the VCCTL software will be described in this paper, and then two case studies will be presented to demonstrate how the software can assist in mixture design and quality testing. RESEARCH SIGNIFICANCE Scientifically based computer models of concrete materials have existed for several decades but, so far, they have not been widely ad