REPAIR OF 130-YEAR OLD MASONRY BRIDGE USING HIGH-PERFORMANCE CEMENT GROUT

The restoration of a masonry bridge pier built in 1887 was carried out using cement-based grout. Erosion of the pointing mortar of the pier core outer surface and cracks and voids in the pier core were encountered. This paper presents the methodology used to develop high-performance cement grouts for injection of deteriorated joints and cracks in the stone pier and describes the repair and monitoring operations. Portland and microfine cement-based grouts were optimized in the laboratory. An epoxy resin grout was used as a benchmark to compare the performance of the cement-based grouts. The effectiveness of the grout injection was assessed with core samples testing and nondestructive testing using the sonic tomography method to compare the quality of the medium before and after grouting. High penetrability of the grout was achieved for the high-performance mixtures. The use of high-early-strength cement with some silica fume replacement resulted in a relatively economical mixture exhibiting high performance. The results of this pilot study were later recommended for the rehabilitation of similar masonry piers.