Use of Non-destructive concrete quality assessment for selective demolition of a highway bridge

Demolition and replacement of the existing transportation infrastructure have increased significantly due to ageing and growth of traffic loads. Consequently, a significant amount of demolition waste of unknown origin is produced. Without knowledge about parent concrete quality only a limited amount of recycled concrete aggregates is used in high-grade applications. This paper presents the framework for selective demolition of a highway bridge by systematic non-destructive concrete quality assessment. Surface chemical composition of concrete structural members was tested with handheld X-Ray Fluorescence Analyzer. In total, 3 columns, 23 beams, one foundation slab and one abutment were assessed. Their compressive strength was estimated using developed conversion curves based on results from rebound hammer and ultrasonic pulse velocity tests and their correlations to cube compressive strength test results. Beams were classified as a high strength (> 80 MPa) members. Columns, foundations and abutments were of a strength lower than 75 MPa. Ordinary Portland cement and silicious aggregates were identified by their chemical composition for nearly all accessible concrete members surfaces. The concrete chemical composition serves as a criterion for future application of fine recycled material. Members were sorted based on strength before demolition. This approach is essential to maximize the potential of the recycled concrete.