If required, concrete core samples are marked and retrieved for petrographic analysis. Cores are used for visual observation, compression testing, split tensile testing, verification of NDT and petrographic analysis. Core locations are selected on the basis of visual observations, hammer soundings and impact-echo testing. Concrete core samples can be shipped to Matergenics for a petrographic analysis.
WHAT IS IT?
A microscopic technique to identify concrete constituents and quality.
Matergenics specializes in Petrographic Analysis, a review of the concrete matrix using microscopic techniques described in ASTM C856 to determine concrete constituents, quality, and cause of inferior performance, distress, or deterioration. Concrete is composed of sand, gravel, crushed rock, or other aggregates held together by a hardened paste of cement and water. Important properties of concrete are: durability (weather resistance, resistance to chemical deterioration, resistance to erosion), workability, water tightness, strength, elasticity, creep, extensibility, and thermal properties. Entrained air content, cement and water content and type, distribution and quality of aggregates are various factors that affect properties of concrete. Estimating future performance and structural safety of concrete elements can thus be facilitated.
Petrography is most often used during failure analyses examinations of concrete structures experiencing distress often from environmental factors. Evidence can be observed for such modes of deterioration as alkali-aggregate reactivity, sulfate attack, freeze-thaw deterioration, carbonation, and expansive phase formation especially in constantly wet conditions. Petrographic examinations can be supplemented with chemical analyses, x-ray diffraction analyses, and scanning electron microscopy.