Computer-based guidelines for concrete pavements.

"February 2005."

Computer-based guidelines for concrete pavements.

"February 2005."

Guide for curing of Portland cement concrete pavements.

"ERDC-CMB 05-021.".

The use of lithium to prevent or mitigate alkali-silica reaction in concrete pavements and structures /

"March 2007."

Texturing of concrete pavements. Interim report no. 2.

Federal Highway Administration, Baton Rouge, La.

Texturing of concrete pavements. Interim report no. 3.

Federal Highway Administration, Baton Rouge, La.

Standard practice for concrete pavements.

"Engineering and design."

Experimental relationships between moduli for soil layers beneath concrete pavements /

Mode of access: Internet.

Standard practice for concrete pavements.

"August 1987."

Accommodating energy price volatility in life cycle cost analysis of asphalt pavements

Energy price is related to more than half of the total life cycle cost of asphalt pavements. Furthermore, the fluctuation related to price of energy has been much higher than the general inflation and interest rate. This makes the energy price inflation an important variable that should be addressed when performing life cycle cost (LCC) studies re- garding asphalt pavements. The present value of future costs is highly sensitive to the selected discount rate. Therefore, the choice of the discount rate is the most critical element in LCC analysis during the life time of a project. The objective of the paper is to present a discount rate for asphalt pavement projects as a function of interest rate, general inflation and energy price inflation. The discount rate is defined based on the portion of the energy related costs during the life time of the pavement. Consequently, it can reflect the financial risks related to the energy price in asphalt pavement projects. It is suggested that a discount rate sensitivity analysis for asphalt pavements in Sweden should range between –20 and 30%.

Implementation of pseudo J-integral based Paris’ law for fatigue cracking in asphalt mixtures and pavements

Pavement analysis and design for fatigue cracking involves a number of practical problems like material assessment/screening and performance prediction. A mechanics-aided method can answer these questions with satisfactory accuracy in a convenient way when it is appropriately implemented. This paper presents two techniques to implement the pseudo J-integral based Paris’ law to evaluate and predict fatigue cracking in asphalt mixtures and pavements. The first technique, quasi-elastic simulation, provides a rational and appropriate reference modulus for the pseudo analysis (i.e., viscoelastic to elastic conversion) by making use of the widely used material property: dynamic modulus. The physical significance of the quasi-elastic simulation is clarified. Introduction of this technique facilitates the implementation of the fracture mechanics models as well as continuum damage mechanics models to characterize fatigue cracking in asphalt pavements. The second technique about modeling fracture coefficients of the pseudo J-integral based Paris’ law simplifies the prediction of fatigue cracking without performing fatigue tests. The developed prediction models for the fracture coefficients rely on readily available mixture design properties that directly affect the fatigue performance, including the relaxation modulus, air void content, asphalt binder content, and aggregate gradation. Sufficient data are collected to develop such prediction models and the R2 values are around 0.9. The presented case studies serve as examples to illustrate how the pseudo J-integral based Paris’ law predicts fatigue resistance of asphalt mixtures and assesses fatigue performance of asphalt pavements. Future applications include the estimation of fatigue life of asphalt mixtures/pavements through a distinct criterion that defines fatigue failure by its physical significance.

Physical and Chemical Performance Testing of Ontario Asphalt Pavements

Thermal and fatigue cracking are the two of the major pavement distress phenomena that contribute significantly towards increased premature pavement failures in Ontario. This in turn puts a massive burden on the provincial budgets as the government spends huge sums of money on the repair and rehabilitation of roads every year. Governments therefore need to rethink and re-evaluate their current measures in order to prevent it in future. The main objectives of this study include: the investigation of fatigue distress of 11 contract samples at 10oC, 15oC, 20oC and 25oC and the use of crack-tip-opening-displacement (CTOD) requirements at temperatures other than 15oC; investigation of thermal and fatigue distress of the comparative analysis of 8 Ministry of Transportation (MTO) recovered and straight asphalt samples through double-edge-notched-tension test (DENT) and extended bending beam rheometry (EBBR); chemical testing of all samples though X-ray Fluorescence (XRF) and Fourier transform infrared analysis (FTIR); Dynamic Shear Rheometer (DSR) higher and intermediate temperature grading; and the case study of a local Kingston road. Majority of 11 contract samples showed satisfactory performance at all temperatures except one sample. Study of CTOD at various temperatures found a strong correlation between the two variables. All recovered samples showed poor performance in terms of their ability to resist thermal and fatigue distress relative to their corresponding straight asphalt as evident in DENT test and EBBR results. XRF and FTIR testing of all samples showed the addition of waste engine oil (WEO) to be the root cause of pavement failures. DSR high temperature grading showed superior performance of recovered binders relative to straight asphalt. The local Kingston road showed extensive signs of damage due to thermal and fatigue distress as evident from DENT test, EBBR results and pictures taken in the field. In the light of these facts, the use of waste engine oil and recycled asphalt in pavements should be avoided as these have been shown to cause premature failure in pavements. The DENT test existing CTOD requirements should be implemented at other temperatures in order to prevent the occurrences of premature pavement failures in future.