Impact of Chemical Deicers-Effectiveness of Early Application of Penetrating Sealants (PDF)

Effectiveness of Early Application of Penetrating Sealants (PDF)

Pdf Summary

The document discusses a study on the effectiveness of early application of penetrating sealants on concrete, conducted by Dan Vruno, P.E., from American Engineering Testing, Inc. in St. Paul, Minnesota. The study considers three independent variables—curing time, type of sealer, and deicer exposure—evaluated at two different levels. The dependent variables assessed are scaling resistance, tested per ASTM C672, and chloride ion ingress, evaluated according to AASHTO T260.<br /><br />The laboratory phase of the study utilized a factorial design, examining combinations of curing times (2, 3, and 4 weeks), types of sealers (8% siloxane, 40% silane, and no sealer), and deicer exposure (calcium chloride and none) to determine scaling resistance.<br /><br />The study results showed that the concrete surfaces treated with 8% siloxane or 40% silane and exposed to calcium chloride demonstrated no scaling (0 rating), whereas surfaces without sealers showed varying degrees of scaling depending on the curing time and deicer exposure. For example, a 4-week curing time with no sealer but exposed to deicer resulted in moderate scaling (3-3.5 rating), whereas a 2-week curing time without sealer resulted in severe scaling (4.5-5 rating).<br /><br />Curing times significantly affected the scaling ratings: longer curing times generally resulted in better scaling resistance. Sealers enhanced resistance, with 8% siloxane performing slightly better than 40% silane.<br /><br />Additionally, the study discussed environmental conditions such as daily temperatures and precipitation from October 2014 to April 2015. The field study results corroborated laboratory findings, emphasizing the importance of selecting appropriate sealers and curing practices to enhance concrete durability against scaling, especially in environments exposed to deicing chemicals.

Keywords

penetrating sealants

concrete durability

scaling resistance

chloride ion ingress

curing time

type of sealer

deicer exposure

factorial design

ASTM C672

AASHTO T260