Uniform TitleAssessment of cracking potential of high-performance concrete due to restrained shrinkage
NameAktas, Kagan (author), Nassif, Hani (chair), Najm, Husamuddin (internal member), Ozbay, Kaan (internal member), Rutgers University, Graduate School - New Brunswick,
SubjectCivil and Environmental Engineering,
Concrete--Expansion and contraction,
DescriptionMany State Engineers have observed that a number of high-performance concrete (HPC) bridge decks exhibited cracking and sometimes soon after being poured. Although deck cracking can be attributed to various causes, in many cases, concrete shrinkage is considered the main contributor. Additionally, concrete in bridge decks is considered restrained and there is a need to examine the behavior of HPC mixes under those conditions.
The AASHTO test (PP 34-06, The Passive or Restrained Ring Test) is employed to measure the cracking potential and restrained shrinkage behavior of various HPC mixes used in bridge deck projects contracted by the New Jersey Department of Transportation (NJDOT). This thesis presents the results of a study which utilized a method for directly measuring the strain development in the concrete ring using Vibrating Wire Strain Gages (VWSG). For each mix, additional tests were performed to determine the corresponding mechanical properties (e.g., elastic modulus, tensile splitting strength, compressive strength, etc.). The effect of total amount of cementitious materials and the potential of cracking for various mixes are also reported. The results of the study are used to correlate strains from restrained shrinkage tests with those from free shrinkage tests. Results show that the coarse aggregate (CA) content, the coarse/fine aggregate ratio, and cementitious content have the greatest effect on both free and restrained shrinkage. Mixes with higher cementitious content were observed to crack earlier. In general, to minimize HPC cracking potential, it is suggested that a limit on free shrinkage (450 micro strain at 56 days) be specified in bridge decks to indirectly reflect restrained shrinkage conditions. Additional limits for the total amount of coarse aggregate (1800 lb/cu yd.) and Coarse/Fine aggregate ratio (1.48) should also be considered.
NoteIncludes bibliographical references (p. 112-114).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.