Methods for evaluating the technical performance of reclaimed bricks

Reusing deconstructed materials and components can help to decrease the environmental burden of buildings. To safely reuse reclaimed items in new construction, methods are needed to reliably identify the essential technical properties of the deconstructed products. This paper looks at salvaged bricks and examines different indirect test methods to assess their properties. The explored test methods include visual observation, pitch of a sound, ultrasonic pulse velocity (UPV), and thin section. Reclaimed clay bricks and calcium silicate bricks were used in the research. They originated from four different buildings and from different kinds of structures. New bricks of the same kinds were also tested for reference and the properties were compared to the reclaimed ones. The assessed properties entail initial rate of water absorption, water absorption capacity, compressive strength, and freeze-thaw durability. The results show that it is possible to assess the deviation of properties and sort out exceptional bricks from a series with visual observation and pitch of a sound. The deviation of different properties can also be assessed with the help of UPV. A correlation was found between UPV and water absorption, compressive strength and freeze-thaw durability. Lower UPV values mean higher water absorption capacity and vice versa. Compressive strength of bricks is clearly lower when the UPV value is low and higher when the UPV is high. Bricks with lower UPV values (< 1.5 km/s) were also found to be freeze-thaw durable while those with higher UPV values (> 3.0 km/s) were found to be non-durable. Between the mentioned two values, the freeze-thaw durability varied. Thin section was only used to assess freeze-thaw durability and it was found to be unreliable as a method.