详情

Internal Curing of Bridge Decks and Concrete Pavement to Reduce Cracking

项目名称：	Internal Curing of Bridge Decks and Concrete Pavement to Reduce Cracking
摘要：	Wisconsin Department of Transportation (WisDOT) has been successfully managing 12,000 total centerline miles of highway system and 5,293 state-owned bridges. The 2016 data shows 98.1 percent of the backbone system and 79.2 percent of the non-backbone system in fair and above condition. Currently 96.9 percent of State owned or maintained bridges have a good rating or fair rating1. Even though the condition of majority transportation system in Wisconsin is in fair or above condition, WisDOT has struggled to control cracking on bridge deck and concrete pavement in our High-Performance Concrete (HPC) and conventional concrete bridge (Grade A) construction projects (Standard Specification Sec. 501 and Sec. 415). Higher strength, lower water to cement ratio (w/c) concrete has been promoted for over 20 years due to the desire for increased strength and reduced permeability. The lower w/c of these concretes makes them susceptible to autogenous shrinkage and cracking. Cracking of concrete leads to ingress of chlorides that also promotes deterioration. Bridge decks have been a primary concern for cracking and deterioration due to the wide, thin, and long pours used coupled with application of deicing chemicals during winter operations. The inability to control cracking in bridge deck and concrete pavement construction leads to deterioration of the concrete transportation infrastructure and shorter life cycles. WisDOT has employed mitigating reactionary strategies like crack sealing and thin polymer overlays to address early age deck cracking. However, these strategies are costly and have impacts on traffic operations due to the need for repeated applications through the life of the structure. WisDOT would clearly benefit from the ability to construct concrete transportation structures that are free from cracking associated with initial construction. In recent years, some DOTs have examined the concept of internal curing of concrete bridge decks and concrete pavement to address the problem of early age cracking by advanced material properties. Internal curing provides moisture used for hydration and offsets moisture loss due to hydration and evaporation. Generally, internal curing is realized by using the pre-wetted expanded lightweight aggregate, recycled concrete aggregates, superabsorbent polymers, or cellulose fibers. It has been documented that internal curing reduces early age shrinkage and associated plastic shrinkage cracking. One of the most important effects of internal curing is that it makes the concrete more resistant to early-age cracking. This technique also makes the concrete less sensitive to variations in the application of curing method. The objective of this research is to examine and document the use of internal curing of concrete in bridge decks and concrete pavement and develop WisDOT specific implementation guidance, tools, and specifications to produce better concrete.
状态：	Active
资金：	194555
资助组织：	Wisconsin Department of Transportation
项目负责人：	Oliva, Bill
执行机构：	CTL GROUP
主要研究人员：	Pacheco, Jose
开始时间：	20181031
预计完成日期：	20201031
实际结束时间：	0