Nanosilica Coatings to Improve the Tensile Bond Strength of Cementitious Grouts

Abstract

The use of prefabricated bridge elements (PBEs) is becoming more common as bridge owners strive to construct robust bridges with minimal impacts on the traveling public. Concrete PBEs offer advantages with regards to quality and construction safety; however, to perform adequately, the installed structural system must include strong, durable connections between the components. Typically, field-cast cementitious grouts are used to connect the PBE. This type of material has at times shown serviceability problems associated to dimensional instability, primarily in the form of shrinkage cracking. A direct consequence is the potential bond degradation between the grout connections and the concrete PBE. This study investigated the use of colloidal nanosilica suspensions as a surface preparation technique to increase the bond strength between the precast components and the field-cast grout. Experimental results, including pull-off bond data and a careful microstructural analysis, strongly suggest that nanosilica coatings interact at the concrete–grout interface to increase the bond strength. A simple initial cost analysis is also discussed.

The Effect of the Addition of Polypropylene Fibers to Primer on the Pull-Off Strength of Epoxy Resin Coatings

“…They found that polyurethane coating has the highest strength and the lowest corrosion rate, while concrete with polypropylene fibers has the highest compressive strength. De la Varga [ 14 ] developed nanosilica coatings to improve the pull-off strength of cementitious materials. Morshed et al [ 15 ] showed that the addition of nanosilica and multi-wall carbon nanotubes to epoxy resin has a positive effect on the bonding between fiber-reinforced polymer composites and concrete.…”