Steven M. Karamihas

ESTIMATION OF RIDEABILITY BY ANALYZING LONGITUDINAL ROAD PROFILE

A method for estimating pavement rideability by computing a statistic called ride number (RN) from measured longitudinal profiles of the pavement is presented. The computational algorithm was developed with two objectives in mind: (a) relevance, as established by correlation between RN and mean panel ratings obtained for profiled pavements, and (b) portability, as determined by the ability of different profiling systems to obtain comparable RN values for profiles taken on the same pavement. Experimental data show that the new algorithm is comparable to previously developed RN algorithms in terms of its correlation with panel ratings. The new algorithm is much more portable; comparable RN values can be obtained from different profilers and the quasistatic Dipstick device. However, measures from ultrasonic profilers are not as accurate, and in some cases these devices are not acceptable for measuring RN. Although the fundamental relationships between profile characteristics and the human perception of ridea...

Use of a ride quality index for construction quality control and acceptance specifications

Profilographs have traditionally been the tool of choice for measurement of newly constructed pavement roughness. Although only a modest relationship exists between profilograph output and ride quality, the construction industry has been reluctant to consider other methods of measurement. In part, this is because a well-established method exists for using a profilograph trace to pinpoint locations that require diamond grinding. In contrast, inertial profilers offer a way to obtain measurements with proven relevance to ride quality and overall pavement performance via analysis by ride quality indexes. A major drawback to using a ride quality index, as cited by the construction industry, is the lack of a method for pinpointing hot spots in pavement that should be corrected by a diamond grinder. A method for locating isolated rough spots on new pavement and a basis for prioritizing the use of a grinder to improve new pavement smoothness by using the inertial profiler output are presented. Rough spots are identified by using an adapted version of the roughness profile, called continuous reporting of ride quality. Isolated irregularities are located by reporting a ride quality index on all possible road segments of a given length. The rough spots located by this method provide a direct snapshot of where events that penalize the overall ride quality most occurred on the pavement. This snapshot provides the road builder feedback that can be used to examine the paving process. A diamond grinding simulation is used to ensure that corrective action is implemented only at locations where a grinder would actually improve ride quality.

Stringline Effects on Concrete Pavement Construction

Modern concrete pavement construction typically uses slipform paving equipment, especially on major highways and airfields. This equipment commonly is guided by its sensing of a stringline set in advance by an engineering survey. Although use of stringline guidance has improved the smoothness of pavement, some limitations of this technique are known to exist. Three of these limitations are explored in detail. The effects on concrete pavement smoothness from the chord effect, the sag effect, and random survey error are described both conceptually and analytically. Of these three effects, random error introduced during the engineering survey is found to be the most pronounced. Furthermore, this analysis shows that contradictions exist within what is sometimes considered good practice for concrete pavement construction; the belief that improved smoothness can be obtained by simply using shorter spacing of the stringline stakes is not always correct. In fact, it is demonstrated that optimum stringline spacing can be realized by recognizing each of the effects described, including the associated costs of mitigation.

ASSESSMENT OF PROFILER PERFORMANCE FOR CONSTRUCTION QUALITY CONTROL WITH SIMULATED PROFILOGRAPH INDEX

The simulated California profilograph index (PI) values produced by repeat measurements from 11 profiling devices on four pavement sections are examined. Repeatability and reproducibility of simulated PI by common profiling devices are discussed, and automated profilograph trace reduction procedures adopted in profilograph simulations are reviewed. The results of profilograph simulations show that the low-pass filter and minimum scallop width are important aspects of trace reduction and should be retained as standard components of simulated profilograph trace reduction. However, criteria are needed to help remove narrow, downward spikes, such as those found in profiles of jointed concrete. The results also show that existing profilers do not agree on PI values sufficiently when a zero blanking band is used.

Experimental analysis of tyre-enveloping characteristics at low speed

In this study, experiments are conducted to investigate tyre-enveloping characteristics. Four different types of tyres are tested. Parameters such as different tyre inflation pressures, vertical loads and types of obstacles (cleats) are considered. In addition to vertical stiffnesses of all tyres, vertical and horizontal force variations while traversing different obstacles at low speed are studied. The effects of inflation pressure and vertical load on variations of force and moment are investigated. Static test results showed that after a certain vertical displacement, all curves in force–deflection diagrams plotted with and without cleat intersect regardless of cleat and tyre types, depending on the inflation pressure of the tyre, which can be called typical static tyre-enveloping characteristics. Test results at low speed show that there is a considerable influence of the vertical load on vertical and lateral force responses of a tyre.

Real-Time Smoothness Measurements on Portland Cement Concrete Pavements During Construction

This report presents the findings of a research study conducted to evaluate and demonstrate real-time smoothness measuring technologies for concrete paving. The work under this study was executed in three distinct but connected phases. Phase I focused on identifying all potential technologies by contacting leading transportation agencies, paving contractors, paving equipment manufacturers, and representatives of concrete pavement associations. Phase II consisted of thorough field evaluation to objectively evaluate the most viable real-time smoothness measuring technologies identified during Phase I, the GOMACO Smoothness Indicator (GSI) and Ames Engineering Real Time Profiler (RTP). Phase III consisted of a series of additional field demonstrations throughout the nation. This report provides documentation of the field data and performance of these technologies as captured during the three project phases. In general, it was found that the two technologies evaluated in the field have reasonable agreement to reference profiles, ability to provide a relative estimate of roughness, and ability to recognize areas where roughness accumulates the most aggressively (i.e., localized roughness).

Profile Analysis of Arizona Specific Pavement Studies 5 Project

This paper characterizes the longitudinal profiles of 11 pavement sections within the Arizona Long-Term Pavement Performance Specific Pavement Studies 5 project throughout their service life. The flexible pavements associated with this project were rehabilitated and monitored as part of the study. Road profile measurements were collected on the in-service pavement before rehabilitation and 12 times over the 16 years afterward. Detailed profile analyses of the sections, including calculating roughness values, examining the spatial distribution of roughness, viewing with postprocessing filters, and examining spectral properties are included here. The value of examining performance with the full suite of methods is demonstrated, and these analyses provided a basis for quantifying and explaining the changes in localized roughness and overall roughness with time as well as for linking profile properties to each sections maintenance history and observations of surface distress. The analysis showed that the two test sections with a 2-in. recycled overlay exhibited the largest postrehabilitation increase in roughness. The two test sections with a 5-in. virgin overlay exhibited the smallest postrehabilitation increase in roughness. Much of the increase in roughness on the roughest test sections was caused by narrow dips at transverse cracks.