Durability of saw-cut joints in plain cement concrete pavements.

794178898Final report.PDFTech ReportFHWA/IN/JTRP-2011/22SPR-3200Joints (Engineering)ConcretePavementsPortland cementPortland cement concreteAbsorptionAcoustic emission testsDeicingFreeze thaw testsHumidityPercent saturationJoint sealersEstersIndianaPurdue University. Joint Transportation Research ProgramCastro, JavierLi, WentingPour-Ghaz, MohammadGolias, MikeTao, BernieSun, HongfangWeiss, W. JasonJoint Transportation Research Program (Ind.)Purdue UniversityIndiana. Dept. of TransportationNTL-HIGHWAY/ROAD TRANSPORTATION-MaterialsNTL-HIGHWAY/ROAD TRANSPORTATION-Pavement Management and PerformanceUS Transportation CollectionThe objective of this project was to evaluate factors influencing the durability of the joints in portland cement concretepavement in the state of Indiana. Specifically this work evaluated the absorption of water, the absorption of deicing solutions,the relationship between the degree of saturation and concrete deterioration, and the role of Soy Mehyl Esters as a potentialconcrete sealant. The aforementioned items were studied in conjunction with the observation of premature joint deteriorationin concrete pavements. Previous work by the PI identified that deteriorating joints were observed to frequently have standingwater and damaged joint sealant. To better understand the potential mechanisms responsible for joint deterioration, a seriesof mortars were tested that are consistent with the mortar fraction of concrete paving mixtures. The first portion of the workexamined the role of deicing salt solutions on the wetting and drying behavior of concrete elements (this was a joint series ofexperiments with SPR 3093). It was observed that salts altered the equilibrium relative humidity of the solution, as suchconcrete containing deicing solutions dried less frequently than concrete containing only pore solution. Further, it wasobserved that the rate of water absorption was related to the square root of ratio of surface tension and viscosity. Saltsolutions have a slower rate of absorption than plain water. It was also observed that concrete previously exposed to deicingsalts also exhibited an altered rate of water absorption. The second portion of the work examined the concept of the degree ofsaturation and its relationship with freeze-thaw damage. Specifically mortars with different air contents were examined.Fagerlund developed a model that proposed a critical degree of saturation could be correlated with the onset of freeze-thawdamage. The work suggests that absorption testing should be used to determine the degree of saturation which can be used toestimate the time to reach a critical degree of saturation. Once this critical degree of saturation was reached freeze-thawdamage was inevitable. While entrained air was observed to slow the time to reach a critical degree of saturation, this criticaldegree of saturation could not be avoided. The final portion of the work examined the potential use of penetrating concretesealers (like soy methyl esters) to reduce water absorption and the corresponding freeze-thaw damage. While absorptiontesting was able to show the benefits of sealers, differences were observed regarding the influence of sealer composition onfreeze-thaw damage