Bituminous materials exhibit a complex mechanical response, and an understanding of the same is paramount in pavement engineering. This course will include introductory elementary linear viscoelasticity, and use that framework to introduce different grading system for bitumen. Use of polymers to enhance the rhelogical properties will be discussed along with the various test methods to quantify such improvement. Mechanical characterization of bituminous mixtures for modulus determination for design purposes as well as quantification for laboratory performance in rutting and fatigue damage will be discussed.
INTENDED AUDIENCE : Highway Engineers
PREREQUISITES : This is a self-contained course for students and practitioners alike, and hence, no prerequisite is required. For those who do not have an undergraduate degree in civil engineering, familiarity with construction of bituminous pavements will be helpful.
INDUSTRY SUPPORT : Engineering Staff working in Oil Refineries, Modified Bitumen Manufacturers, State, and Central Highways Departments and PWD, Ministry of Road Transport and Highways, and National Highways Authority of India.
COURSE LAYOUT Week 1: Outline of the course; Introduction to bituminous pavements; Overview of distresses such as rutting and fatigue cracking in bituminous layers; Influence of binders and mixtures on such distresses; Role of mechanical characterization for design and laboratory performance.
Week 2:Introduction to linear viscoelasticity; Elastic, viscous and viscoelastic response; Viscoelastic solid and viscoelastic fluid; Linearity of response - scaling and superposition;
Week 3:Introduction of material functions for viscoelastic materials - creep compliance function and, stress relaxation function in the time domain and complex creep compliance and complex stress relaxation function in the frequency domain.
Week 4:Influence of temperature on the linear viscoelastic response; Thermorheologically simple behavior, time-temperature superposition, and construction of master curve.
Week 5:Introduction to refinery processing of bitumen; Chemical composition of bitumen; Relationship between chemical composition and physical parameters of bitumen; Aging of bitumen and bituminous mixtures.
Week 6:Introduction to the grading system for bitumen; Penetration and viscosity grading of bitumen
Week 7:Industry lecture on Dynamic Shear Rheometer - Dharmesh Gala from Anton Paar; Performance grading of bitumen - Issues related to reliability, slow-moving traffic, and high volume and grade-bumping.
Week 8:Modifiers for bitumen; Performance characterization of modified bitumen; Introduction to MSCR test method.
Week 9:Introduction to Bituminous Mixture and the associated volumetrics; Mixing and compaction of unmodified and modified bituminous mixtures
Week 10:Stiffness modulus (van der Poel), dynamic modulus, and resilient modulus of bituminous mixtures - experimental protocol, and post-processing.
Week 11:Simulation of rutting of bituminous mixtures in the laboratory: flow number, flow time and dry rut wheel testing - experimental protocol, and post-processing.
Week 12:Simulation of fatigue damage of bituminous mixtures in the laboratory: beam bending and repeated indirect tensile testing - experimental protocol, and post-processing.