National Concrete Pavement Technology Center

Project description

The objectives of this study were to assess the use of penetrating sealers to protect concrete pavement joints and to evaluate its cost-effectiveness. Evaluations were first conducted on in-service pavements on I-94, I-41, and I-39 where penetrating sealer was applied. Controlled laboratory tests were completed to investigate the impact of sealer type, application time, application rate, and application method. The best practice was implemented in a field study on I-39. Although there was no visual detection of the presence of sealers in in-service pavements previously treated with sealers, laboratory tests proved the presence and functionality through contact angle, absorption, and penetration depth. The depth of penetration ranged from 1.46 mm (0.06 inch) to 11.75 mm (0.46 inch), with an average of 5.14 mm (0.20 inch). A general trend of decreasing effectiveness along years of service was observed. However, when compared with the samples without sealer, more than half of the joints with sealer were still performing better in terms of contact angle and absorption after 8.2 years of service. The laboratory study found that all penetrating sealers applied to concrete samples resulted in decreased absorption and extension of time to critical (85%) saturation. For the “A-FA” concrete, the silane applied in dry condition extended the time to critical saturation 8 times longer than the control sample without silane, indicating silane’s capability of extending the service life of concrete. Core samples from the field study section were hydrophobic with contact angle exceeding 90°. There was no difference in time to critical saturation and no sign of sealer presence in the penetration depth test. The absence of sealer in the field study section was attributed to three possible reasons: (a) high-performance concrete has very low permeability, (b) the polished concrete after saw-cutting is hydrophobic, and (c) vertical surface is challenging for effective coverage. Penetrating sealer may not provide its intended function for low permeability concrete or when it cannot be practically applied to a vertical surface with sufficient penetration. However, the findings of this study are limited to the collected project data.