Lankard Materials Laboratory, Inc. supports producers and users of portland cement concrete and other inorganic cement-based building and construction materials. Petrographic examinations are conducted on raw materials used in the manufacture of these materials and on samples of materials taken from service. Conclusions and recommendations derived from the findings of petrographic examinations and related laboratory testing meet a number of needs:
• Guidelines for the selection of suitable cements and aggregates for use in the manufacture of concretes and other cement-based materials.
• Assessment of the factors involved when concrete or other cement-based materials do not meet expectations or performance requirements in service.
• Providing a basis for identifying an optimum repair or remediation strategy for constructions that have deteriorated to an unacceptable level.
• Information for engineers conducting condition surveys on the expected role that the cement-based material can play in an overall rehabilitation scheme.
Laboratory investigations are conducted in accordance with the guidelines of ASTM C856 (Standard Practice for Petrographic Examination of Hardened Concrete), ASTM C295 (Standard Practice for Petrographic Examination of Aggregates for Concrete), and ASTM C457 (Standard Test Method for Microscopical Determination of Parameters of the Air Void System in Hardened Concrete). The tools used in laboratory investigations include optical microscopy (reflected and transmitted light), scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction. Data are also obtained where appropriate on compressive and flexural strength, modulus of elasticity, and density.