Office of Rigid Pavement Materials and Structural Concrete

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Materials Engineering and Testing Services -
Office of Rigid Pavement Materials and
Structural Concrete

The Office of Rigid Pavement Materials and Structural Concrete is the focal point for Caltrans’ concrete needs. New specifications and test methods are currently being written to keep Caltrans up to date with the latest concrete practices. The Office consults with District personnel and makes recommendations for both new projects and the rehabilitation of existing projects. Four sections comprise Rigid Pavement, and they provide technical expertise, recommendations and quality assurance testing for the cement, aggregate and concrete used in highway projects.

        
Paving Interstate 80 in Placer County with dowel bar baskets
and a recently paved stretch of Highway 58 in Mojave.

• The Concrete Consultations and Investigations section provides the Districts with information and field support using the latest concrete techniques and concrete related materials. They offer training and information on the specific uses of construction materials and are continuously developing new California Test Methods and specifications for on-going projects. Typical projects include the development and use of the maturity concept for determining the in-place strength of concrete placements, the development of rapid-set concrete using special admixture combinations, and the new flowable concrete mixes. The Concrete Consultations and Investigations section is instrumental in assisting field personnel in solving concrete placing and related dowel installation problems.


• The Aggregate Section determines if the aggregates proposed for use in Portland cement concrete on State contracts comply with the California Standard Specifications and ASTM Standards. The tests performed to determine compliance include: grading, specific gravity, absorption, sand equivalent, Los Angeles Rattler, cleanness value, durability, soundness, color, crushed particles and R-value.


• The Cement Section performs tests on the cement used in Portland cement concrete to determine if they comply with the California Standard Specifications and ASTM Standards. These tests include Blaine fineness, compressive strength of mortar cubes, consistency, setting time, autoclave expansion and shrinkage of mortar bars. The Cement Section also performs sand mortar testing for the Aggregate Section


• The Concrete Section produces concrete mixes that may be used to check on a Contractor’s proposed design or to determine the amount of cement required to produce concrete of a specified strength. Concrete can be tested for compressive and flexural strength, modulus of elasticity, shrinkage of concrete specimens, and freeze-thaw resistance for concrete to be used in mountain areas. Fast setting materials are tested for repair and rehabilitation of concrete structures, which include the use of polyester and methacrylate resins. Additionally, the Section tests aggregate and concrete for alkali silica reactivity (ASR) as well as chlorides and the cement content of hardened concrete.