Ali Maher

UTILIZATION OF CONSTRUCTION AND DEMOLITION DEBRIS UNDER TRAFFIC-TYPE LOADING IN BASE AND SUBBASE APPLICATIONS

As construction and remediation take place throughout New Jersey, the amount of construction and demolition debris increases, while the availability of landfill space decreases. A viable solution for disposing of these materials is to incorporate them into base and subbase applications. An extensive laboratory program was conducted on two types of construction and demolition debris: recycled concrete aggregate (RCA) and recycled asphalt pavement aggregate (RAP). These two materials were compared with dense-graded aggregate base coarse (DGABC), which currently is being used in roadway base applications in New Jersey. Both RCA and RAP were mixed at various percentages with the DGABC to evaluate whether an optimum mix blend could be formulated. The materials were evaluated under a traffic-type loading scheme that included resilient modulus and permanent deformation via cyclic triaxial testing. Laboratory tests indicated that the RAP, RCA, and DGABC blended materials all obtained higher resilient modulus values than the currently used DGABC. The permanent deformation results indicated that the RCA mixed samples obtained the lowest amount of permanent deformation when the material was cyclically loaded to 100,000 cycles. In contrast, the permanent deformation testing on RAP mixed samples resulted in the highest amount of permanent deformation at the same number of cycles. Existing models currently used for quarried base and subbase materials were used to predict the permanent deformation in the recycled materials. Laboratory test results indicated that these models could be used for predicting permanent deformation in unbound recycled materials.

Mechatronic Systems Design for an Autonomous Robotic System for High-Efficiency Bridge Deck Inspection and Evaluation

The condition of bridges is critical for the safety of the traveling public. Bridges deteriorate with time as a result of material aging, excessive loading, environmental effects, and inadequate maintenance. The current practice of nondestructive evaluation (NDE) of bridge decks cannot meet the increasing demands for highly efficient, cost-effective, and safety-guaranteed inspection and evaluation. In this paper, a mechatronic systems design for an autonomous robotic system for highly efficient bridge deck inspection and evaluation is presented. An autonomous holonomic mobile robot is used as a platform to carry various NDE sensing systems for simultaneous and fast data collection. The robots NDE sensor suite includes ground penetrating radar arrays, acoustic/seismic arrays, electrical resistivity sensors, and video cameras. Besides the NDE sensors, the robot is also equipped with various onboard navigation sensors such as global positioning system (GPS), inertial measurement units (IMU), laser scanner, etc. An integration scheme is presented to fuse the measurements from the GPS, the IMU and the wheel encoders for high-accuracy robot localization. The performance of the robotic NDE system development is demonstrated through extensive testing experiments and field deployments.

Influence of Pavement Surface Type on Tire/Pavement Generated Noise

Pavement noise evaluations were conducted on 42 pavement surfaces in New Jersey using the Close Proximity Method (CPX) via the NCAT Noise Trailer. The CPX Method is a current ISO Standard that measures sound levels of the tire/pavement interface, thereby providing a method to evaluate solely the influence of pavement surface on traffic noise. The surfaces were comprised of both hot mix asphalt (HMA) and Portland cement concrete (PCC) surfaces. The HMA surfaces consisted of dense-graded asphalt mixes (DGA), open-graded friction course (OGFC) with and without crumb rubber, stone-mastic asphalt (SMA), NovaChip®, and a microsurfacing slurry mix. The PCC surfaces, pavements and bridge decks, had varying surface treatments consisting of transverse tining, saw-cut tining, diamond grinding, and broom finish. The main focus of the research was to: 1) Evaluate how different pavement surfaces influence the generation of tire/pavement noise, 2) Evaluate the effect of vehicle speed on the tire/pavement generated noise, and 3) Provide guidance as to the repeatability of the CPX method and optimal test distance on the roadway to aid in maximizing testing efficiency. Results of the testing indicated that the asphalt based surfaces provided the lowest tire/pavement noise levels. Of the HMA surfaces tested, the OGFC mixes modified with crumb rubber provided the lowest noise levels (96.5 dB(A) at 60 mph (96.5 km/h)). However, not only were these mixes modified with crumb rubber, but they also had the finest aggregate gradation. The loudest HMA surface was a 12.5mm SMA mix (100.5 dB(A) at 60 mph (96.5 km/h)). The PCC surfaces had the highest noise levels. Of all PCC surfaces tested, the transverse tined surface obtained the loudest noise levels (106.1 dB(A) at 60 mph (96.5 km/h)). It was found that if the PCC surface was diamond ground, the noise levels could be comparable, and sometimes lower, than typical HMA pavement surfaces. Typical noise levels of the diamond ground PCC surfaces were approximately 98.7 dB(A) at 60 mph (96.5 km/h). To evaluate the effect of vehicle speed, noise measurements were conducted at 55, 60, and 65 mph (88.5, 96.5, and 104.6 km/h). Test results within this range indicate that on average, the tire/pavement noise increases linearly and at a rate of approximately 0.18 dB(A) for every 1.0 mph (1.6 km/h). The NovaChip® mixes were less susceptible to the increase in vehicle speed (0.15 dB(A) increase for every 1.0 mph (1.6 km/h) increase), while the PCC broom finish (no treatment) surfaces were affected the greatest by vehicle speed (0.29 dB(A) increase for every 1.0 mph (1.6 km/h) increase). The CPX method was found to be repeatable, with an average standard deviation of approximately 0.13 dB(A), as long as the test distance was greater than 0.2 miles (0.32 km). This is most likely due to the sensitivity of the test method being influenced by the ability to track the identical wheel-path in successive test runs.

Influence of Production Temperature and Aggregate Moisture Content on the Initial Performance of Warm-Mix Asphalt

The concept and use of warm-mix asphalt (WMA) is becoming more popular in the asphalt industry. The promise of reduced energy consumption, reduced emissions, and a more workable product is appealing to an industry pressured by environmentalists with sustainability agendas and state agencies that apply pay adjustments on the bases of ride quality and pavement density. The use of WMA may come with some potential issues, however. Lower production temperatures may result in softer asphalt because of reduced oxidative aging, while poorly dried aggregates may create a problem from moisture damage. To evaluate these issues, a research project was undertaken to quantify the influence of mixing (production) temperature on the rutting and fatigue cracking performance of WMA mixtures. Stripping potential was also evaluated by using prewetted aggregate blends and by modifying the mixing procedure in the laboratory to more appropriately simulate a drum plant production of WMA. The laboratory procedure clearly indicated a decrease in rutting resistance and stiffness when evaluated in an asphalt mixture performance tester and dry Hamburg wheel tracking (HWT) tests once mixing temperatures decreased. Fatigue cracking resistance meanwhile increased in an overlay tester. Tensile strength ratio (TSR) and wet HWT tests indicated that TSR and Hamburg rutting values were able to obtain only passing results at conventional hot-mix asphalt mixing temperatures and with dry aggregates. The information presented may help state agencies to develop quality control testing plans for future implementation of WMA.

SEISMIC METHODS IN POST CONSTRUCTION CONDITION MONITORING OF BRIDGE DECKS

Ultrasonic methods implemented in various types of integrated seismic devices can be successfully used in quality control and condition assessment of bridge decks. Of special interest are three ultrasonic techniques: ultrasonic body-wave (UBW), ultrasonic surface-wave (USW), and impact echo (IE). While the first two are used in a deck material characterization, the IE method is primarily used in evaluation of a corrosion induced delamination. The biggest advantages of the IE method over a current practice of chain dragging is that it allows detection of zones of delamination at various stages: from initial to progressed and developed, thus enabling better prediction of deterioration processes in the deck. To improve automation, accuracy and interpretation of results of the IE technique, the testing is simulated by the finite element method. Numerous finite element results confirm the ability of the IE method to accurately measure the position, extent and the stage of delamination. The finite element method was successfully used in simulation of two probable scenarios of delamination progression: expansion/growth of a single small delamination, and progressive linking of several smaller delaminations. Elements that can be used in recognition of the two processes are described and can be used in long term monitoring and prediction of deterioration processes. Issues related to finite element modeling of wave propagation in bridge decks and finite element analysis results interpretation are discussed too.

Autonomous robotic system for high-efficiency non-destructive bridge deck inspection and evaluation

Bridges are one of the critical civil infrastructure for safety of traveling public. The conditions of bridges deteriorate with time as a result of material aging, excessive loading, and inadequate maintenance, etc. In this paper, the development of an autonomous robotic system is presented for highly-efficient bridge deck inspection and evaluation. An autonomous mobile robot is used as a platform to carry various non-destructive evaluation (NDE) sensing systems for simultaneous and fast data collection. Besides the NDE sensors, the robot is also equipped with various onboard navigation sensors. A sensing integration scheme is presented for high-accuracy robot localization and navigation. The effectiveness of the autonomous robotic NDE system is demonstrated through extensive experiments and field deployments.

Impact Echo Data from Bridge Deck Testing: Visualization and Interpretation

Accurate assessment of the condition of bridges leads to their economic management. Ultrasonic seismic methods can be successfully used for this purpose through evaluation of changes in material characteristics and detection of the development of defects and zones of deterioration. The impact echo (IE) method is of special benefit in evaluation of corrosion-induced deck delamination, due to the methods nondestructive nature, speed of evaluation, and ability to detect delaminated zones at various stages of deterioration: from initial to progressed and developed. The traditional approach in condition assessment of bridge decks by IE on the basis of review of individual test point records and a new automated approach based on three-dimensional (3-D) data visualization are presented. The developed 3-D visualization platform allows both the advanced presentation and interpretation of IE data. The data presentation is provided as 3-D translucent visualizations of reflectors in a bridge deck section and horizontal and vertical cross sections through all distinctive zones, including a zone of delamination. The associated interpretation platform allows both (a) the overall assessment of the condition of the deck, through cumulative distributions and histograms of reflection intensity, and (b) identification of deteriorated zones of the deck for repair or rehabilitation in an efficient and intuitive way. The visualization platform effectively enables an IE device to be used as a type of bridge deck sonar device.

Field Placement and Evaluation of Stabilized Dredged Material (SDM) from the New York/New Jersey Harbor

Since the 1997 local ban on ocean dumping of dredged sediments, the States of New York and New Jersey have pursued a policy of environmentally sound solutions to the management of dredged material, including beneficial use of stabilized dredged material (SDM) in transportation applications. A pilot study was initiated in 1998 to evaluate the use of SDM in the construction of highway embankments. Utilizing 80,000 cubic yards of dredged material, two embankments were constructed from SDM on a commercial development area adjacent to the Harbor. Geotechnical properties and handling of SDM were evaluated both during and one year post − construction. This article presents the evaluation of the embankments themselves, including constructability and performance. The results demonstrate that SDM satisfies most of the geotechnical criteria for fill construction, except those for durability, requiring proper coverage and protection similar to that provided for fills constructed on cohesive soils. This same characteristic precludes long term stockpiling of SDM prior to final placement, limiting applications to those that have schedules overlapping with dredging projects. Increased costs for the use of SDM can be as high as

Geotechnical Properties of Stabilized Dredged Material from New York-New Jersey Harbor

8 per cubic yard over traditional fills; however, this cost may be recouped through management fees collected from dredging projects.

Rapid Bridge Deck Condition Assessment Using Three-Dimensional Visualization of Impact Echo Data

As a result of the ban on the disposal of contaminated dredged sediments in the New York Bight, the states of New York and New Jersey have embarked on a rigorous program of seeking environmentally friendly solutions to handling dredged material, including beneficial use of stabilized dredged material (SDM) in roadway applications. A pilot study was initiated in 1998 to construct two embankments on a site in Elizabeth, New Jersey, where SDM was successfully used as a cover for more than 100 acres of commercial development area. The pilot study included a laboratory phase for geotechnical evaluation of SDM and a field phase for monitoring and evaluating the construction process as well as the performance of the fills after construction. The results of the laboratory phase indicate that SDM satisfies most geotechnical criteria for fill construction—except those for durability—requiring proper coverage and protection similar to those provided for fills constructed on cohesive soils.