Concrete Laboratory

Purpose: Researchers in the Concrete Laboratories evaluate new test methods, conduct concrete materials research, develop mixture design and analysis procedures for concrete pavements, and provide concrete forensics.

Laboratory Description: This laboratory is comprised of five components. These include an Aggregate Materials and Sample Preparation room, and a Curing Room as well as facilities for evaluating plastic concrete properties along with rheology, setting, and calorimetry; concrete curing and volume change; concrete durability, including freezing and thawing and alkali-silica reaction; and mechanical properties, including strength and modulus of elasticity.

Laboratory Capabilities: Facilities exist for the preparation of aggregate samples for concrete and the preparation of hardened cement paste, mortar, or concrete specimens for testing and analysis, for batching and mixing cement paste, mortar, and concrete; and for performing tests on fresh (plastic) cement paste, mortar, and concrete. A Curing Laboratory is available for curing of concrete specimens under standard or other controlled conditions and assessment of curing-related properties, such as degree of hydration, maturity, and shrinkage. The Concrete Durability Laboratory provides facilities for investigating the effects of chemical and environmental exposure on concrete. It is equipped to assess, alkali-aggregate reaction; sulfate attack; chloride penetration; freezing, thawing, and thermal effects. The Mechanical Properties Laboratory provides facilities for testing the mechanical properties of concrete, steel, and composites. A Petrographic Laboratory is available for preparing and conducting petrographic and microscopic investigations of aggregate, Portland cement concrete, and asphalt concrete. The laboratories are inspected by the Cement and Concrete Reference Laboratory and accredited by the American Association of State Highway and Transportation Officials Materials Reference Laboratory both located at National Institute of Standards and Technology.

Laboratory Equipment: The Aggregate Materials and Sample Preparation Laboratory equipment includes two rock crushers, a pulverizer, a vibrating screen, a Gilson TestMaster, standard sieves, a Videograder (for automated sizing and shape analysis of aggregate), two water-cooled saws, lapping wheels, a lathe for profile grinding, and a muffle furnace. The Plastic Concrete Laboratory has two drum mixers and a two-cubic-foot pan mixer for mixing concrete, mortar and paste planetary mixers, a high shear paste mixer, VeBe, Air Void Analyzer, DSR rheometer, semi-adiabatic calorimeter and isothermal calorimeter. The Concrete Curing laboratory equipment includes three heated curing tanks, two walk-in environmental chambers [8ft by 8 ft], and [50 gallon] water bath. The Concrete Durability Laboratory equipment includes an automated freeze-thaw, chamber with the capacity for 17 specimens, thermal coefficient of expansion test frames (both developed in-house and commercial units) and bath, and computer-controlled chloride penetration test equipment. The Mechanical Properties Laboratory equipment includes three servocontrolled universal testing machines with capacities ranging from 267 kN to 1,780 kN (60,000 lbs. to 400,000 lbs.), a 4,448 kN (1,000,000-lb.) compression testing machine, a compressometer/extensometer, and four creep frames.

Laboratory Services: The Concrete Laboratories provide support in the following areas: investigating the properties and performance of Portland cement concrete and its component materials (cement, aggregate, supplementary cementitious materials (SCMs) admixtures, etc.); evaluating and developing new or improved equipment and procedures for assessing properties and performance of Portland cement concrete including practices for materials selection, mixture proportioning, and construction of Portland cement concrete; mixing, casting, and testing of Portland cement concrete test specimens in support of other researchers at the Turner-Fairbank Highway Research Center; specialized testing and forensic investigations on Portland cement concrete to assist State departments of transportation in research and troubleshooting problems with existing pavements and structures.