Field Implementation of Rubberized Chip Seal

Chip seals have been widely used as a pavement maintenance surface treatment due to its competitive cost and construction time. Recently, the research team developed a rubberized chip seal where natural aggregate is replaced with crumb rubber obtained from recycled tires. During this study, a total of 108 laboratory specimens and a field chip seal section with different crumb rubber replacement ratios were investigated. Aggregate macrostructure, retention, and skid resistance were measured. The crumb rubber showed a remarkable performance in aggregate retention measured using the Vialit and Pennsylvania tests. The values of the mean texture depth of rubberized chip seal specimens were significantly higher than those of the conventional chip seal. Finally, while a reduction in the British Pendulum Number (BPN) was recorded with an increase in the crumb rubber replacement ratio immediately after construction, after a period of more than a year of service life in the experimental section road, the rubberized chip seal segments recorded a much higher BPN compared to that of the conventional chip seal segment. Furthermore, it is recommended also to increase the curing time for chip seal, regardless of aggregate type, to at least six hours to improve the performance of the chip seal.

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Report number: cmr18-012
Published: December 2018
Project number: TR201804
Authors: Ahmed Gheni, Alireza Pourhassan, Mohamed ElGawady, Yasser Darwish, and William Schonberg
Performing organization: Missouri University of Science & Technology

Characterization and Performance of Zero-Cement Concrete

This study has investigated the feasibility of using five different types of class C fly ashes (FAs)  sourced from Labadie, Jeffrey, Kansas City, Thomas Hill, and Sikeston power plants in the state of Missouri to synthesize zero-cement concrete (ZCC) for different structural and repair applications. Alkali activator (Alk) consisting of sodium silicate (SS), Na2SiO3, and sodium hydroxide (SH), NaOH were used to synthesize the ZCC. Slag, crumb rubber, and air-entraining admixture (AEA) were used in a few mixtures as additives to improve the durability of the ZCC. Approximately 300 mortar and concrete mixtures were prepared during this study to investigate the mixing procedure, water/FA, Alk/FA, SS/SH, curing regime, fresh properties, mechanical properties, durability, repair applicability, and cost analysis of the ZCC. A 5000 psi MoDOT conventional concrete (CC) mixture was also prepared and tested for comparison purposes. This study revealed that ZCC can be used as a replacement for CC. ZCC showed good workability and adequate compressive strength for structural applications ranging from 3,660 psi to 7,465 psi based on the curing regime and source of FA. Some ZCC mixtures successfully passed 300 cycles of freeze and thaw per ASTM C666-15 procedures A and B. Furthermore, the drying shrinkage values of the ZCC specimens at all ages were significantly lower than those of the corresponding CC specimens. ZCC also presents higher corrosion resistance compared to CC. ZCC mixtures have a low to moderate permeability and chloride ion penetrability, while the CC mixture showed a high permeability and chloride ion penetrability. Finally, ZCC can be used as a repair material for existing concrete structures. The bond between ZCC as a repair material and CC as a host material was adequate and comparable to the bond between CC and CC.

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Report number: cmr18-011
Published: December 2018
Project number: TR201614
Authors: Eslam Gomaa, Simon Sargon, Cedric Kashosi, Ahmed Gheni, Mohamed ElGawady, William Schonberg
Performing organization (s): Missouri University of Science & Technology

Pavement Roughness Measurement Using Android Smartphones: Case Study of Missouri Roads and Airports

Keeping airport pavement in good condition requires accurate and timely data on existing pavement conditions. Since many existing pavement survey methods can be costly and labor intensive, there is a need for simple and low cost tools to facilitate the evaluation of airport pavement condition for smaller airports with limited resources. To address this need, a study was undertaken to evaluate an android smartphone application for use in assessing airport pavement condition. To perform this evaluation, an initial validation study was performed on two sections of I-70 in central Missouri. The smartphone application was utilized to collect IRI data for all 27 of the state funded general aviation airports in Missouri. The data were then analyzed and compared with the construction and maintenance records for the airports. The study found that the smartphone application (app) has the potential to be an effective low cost tool for assessing airport pavement condition. The smartphone estimated IRI values were close to those measured by ARAN. The measured IRI data classified most of the test sections in agreement with MAP-21 requirements. The obtained trends agreed well with the construction and maintenance records of the airports. An equation was developed to predict PCI based on the IRI values measured from the smartphone application. Future enhancements to the research could include the use of more vehicles and smartphones and the use of aircraft cab acceleration data. An improved graphical-user interface (GUI) should be developed for transfer of the app to airport managers.

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Report number: cmr18-010
Published: August 2018
Project number: TR201709
Authors: William G. Buttlar, Amir Alavi, and Henry Brown with graduate students Henry Sills, Amanda Mesa and Elizabeth Okenfuss
Performing organization (s): University of Missouri-Columbia for UAViation

Unmanned Aircraft Systems: An Overview of Strategies and Opportunities for Missouri

Many states have embraced Unmanned Aircraft Systems (UAS) and are actively utilizing the technology across a number of state and local agencies.  A growing number of states’ Departments of Transportation (DOT) are leveraging innovative UAS technology to creatively improve safety and efficiency while saving money. Currently 35 state DOTs are exploring, researching, testing, or using UAS. The Missouri Highways and Transportation Commission launched a comprehensive research project to develop a new Missouri State Airport System Plan (MSASP), which included UAS – commonly referred to as drones. This research explored the adoption of UAS technology at the national and state levels – focusing on the role of transportation agencies, activities, policies, and strategies promoting safe UAS operations and economic growth.  The national level was a macro look at the broader UAS adoption across the country. At the state or micro level, researchers evaluated five states within the same central United States region as Missouri. The micro level research focused more narrowly on the states’ strategies, policies, activities, and the role of state agencies regarding UAS adoption. Researchers evaluated these findings along with the UAS ecosystem in Missouri, identified strategic opportunities and developed recommendations that may help accelerate Missouri’s adoption of UAS, while promoting economic growth and preparing Missouri for future UAS opportunities.

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Report number: cmr18-009
Published: June 2018
Project number: TR201808
Authors: Damon Lercel and Richard Steckel (UAViation)
Prepared for: Joe Pestka, Jviation, Inc.

Foundation Reuse: Length, Condition, and Capacity of Existing Driven Piles

Reusing existing bridge foundations is an appealing design alternative for many bridge projects, but methods for investigating and analyzing existing foundations vary widely. Researchers from the University of Missouri performed research to evaluate various methods for predicting the installed length, assessing the condition, and predicting the load capacity of existing foundations. The methods were evaluated via application to two MoDOT bridges, both built in the 1960s and replaced in 2017. One bridge was founded on driven closed-end steel pipe piles backfilled with concrete (CIP piles), and the other was founded on octagonal precast concrete piles. The foundations were not actual candidates for reuse, but were selected for study because of the age and type of piles. To perform the evaluations, researchers gathered and made predictions from historical records, performed various geophysical test methods to predict pile length and potentially identify deterioration, performed static load testing, performed high-strain dynamic analyses of pile restrikes, and exhumed the piles to assess true pile length and condition.

The research found that historical pile driving records could be used to predict pile length within 3 percent of the exhumed length whereas values from as-built plans were as much as 30 percent less than the exhumed length. Results from parallel seismic testing produced estimates of pile length that were within 8 percent of the exhumed length. Parallel seismic results were more accurate when the sensor was located within 5 ft of the pile. MoDOT’s seismic cone penetration test (SCPT) rig was effective for parallel seismic tests. Sonic Echo / Impulse Response test methods performed after bridge demolition were effective in predicting pile lengths for the CIP piles, but application to the precast piles underpredicted lengths by as much as 20 percent, most likely because of the taper in the precast piles. SE/IR tests performed prior to bridge demolition were mostly inconclusive, mostly because of complex vibrations between the pile and connected superstructure. Observations of exhumed piles for both CIP and precast piles revealed no significant deterioration. CIP piles had visible surface corrosion, but caliper measurements of wall thickness at sections cut through the most corroded portions were not significantly different from measurements through portions without visible corrosion. Estimates of axial load capacity of the existing foundations varied widely. Values listed on historical documents were the least, and quite conservative compared to values from static load testing. The CIP test pile was loaded to four times the historical design capacity, and the precast test pile was loaded to seven times the historical design capacity. Maximum load test values can be considered lower bound values since the tests terminated upon failure of the capping beam for the existing bridge, which was used as the reaction. Dynamic analysis of restrike data yielded estimates of axial capacity similar to the maximum loads applied during static load testing. The dynamic values are also lower bound values because the restrike hammer had insufficient energy to transfer significant load to the pile tips.

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Report number: cmr18-008
Published: May 2018
Project number: TR201714
Authors: Andrew Z. Boeckmann, Brent L. Rosenblad, and John J. Bowders
Performing organization: University of Missouri-Columbia Dept. of Civil and Environmental Engineering

Missouri's Bond Strength Investigation

Delamination or debonding between asphalt layers is a persistent problem often encountered when analyzing pavement cores taken from Missouri’s roadways.  Delaminated asphalt layers are suspected to be the primary cause of premature pavement deterioration that dramatically decreases the pavement’s service life. After a thorough review, the Missouri Department of Transportation (MoDOT) increased their minimum tack coat application rates to more closely follow national recommendations and guidelines in order to mitigate the issues with delaminated asphalt lifts.  This report presents the findings of a tack coat investigation conducted by MoDOT to evaluate and verify the effects of the tack coat specification change.  The source of the data and information presented in the report is from a laboratory study and field studies that evaluated the bond strength of asphalt overlays between different surface types, tack coat products, varied application rates, and environmental conditions. The laboratory study evaluated different tack coat products for bond strength between two lifts of new asphalt and between new asphalt and concrete.  The laboratory study subjected a set of each tack product to freezing temperatures to monitor the effects of cold temperature.  Also, the application rates were varied to determine the most optimal rate for adequate bond strength.


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Report number: CM 2018-01
Published: May 2018 (originally submitted January 2015)
Project number: Internal research
Authors: Jason M. Blomberg and Paul T. Denkler
Performing organization: Missouri Department of Transportation Construction and Materials Division Pavements Section

Evaluation of Green Lights on TMAs

The use of green versus traditional amber lights on Truck Mounted Attenuators (TMAs) was investigated to see if their use could help to improve safety in mobile work zones. Four light color configurations were evaluated via a combination of simulator and field study: amber/white, green only, green/white, and green/amber. The TMAs were used as shadow vehicles representing mobile work zones and were equipped with flashing light bars, an arrow board, and a checkerboard sign with steady light bulbs. Driver behavior measures, including first blinker distance and speed, merge distance and speed, work zone and arrow direction recognition distance, and disability glare were captured in simulator tests. Vehicle speeds as they passed TMAs were recorded in both the simulator and field studies. The simulator study results indicated that the amber/white combination had the highest visibility of work zone but created the highest level of concern with disability glare. The green only configuration yielded the least disability glare but also low overall visibility. The study findings implied an inverse relationship between visibility (awareness of work zone) and arrow board recognition (easy on eyes). The green/amber TMA light configuration performed roughly between the two aforementioned configurations and was the configuration preferred by the participants in a post simulator survey. The field study found that the green only TMA slowed drivers down when they passed the mobile work zone, and lower TMA speeds led to lower vehicle speeds. The results did not point in a single direction for both the simulator and field tests, and all four configurations appear to be viable.

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Report number: cmr18-007
Published: May 2018
Project number: TR201722
Authors: Henry Brown, Carlos Sun, Praveen Edara, Siyang Zhang, and Zhu Qing
Performing organization: University of Missouri-Columbia Dept. of Civil and Environmental Engineering

Design and Performance of Cost-Effective Ultra High Performance Concrete for Bridge Deck Overlays

The main objective of this research was to develop a cost-effective ultra-high performance concrete (UHPC) for bonded bridge deck overlays. The high durability and mechanical properties of such repair material can offer shorter traffic closures and prolong the service life of the bridge deck. The UHPC was optimized using supplementary cementitious materials (SCMs), proper combinations of sands, and adequate selection of fiber types and contents. Packing density studies included paste, sand, and fiber combinations. The robustness of optimized UHPC mixtures to variations of mixing and curing temperatures was examined. The efficiency of various shrinkage mitigation approaches for reducing autogenous and drying shrinkage of optimized UHPC mixtures was evaluated. This included the use of CaO-based and MgO-based expansive agents, shrinkage-reducing admixture, and pre-saturated lightweight sand. Test results indicate that the optimized UHPC mixtures exhibited relatively low autogenous shrinkage and drying shrinkage. All tested UHPC mixtures exhibited high mechanical properties and excellent frost durability. The use of 60% lightweight sand led to a significant reduction in autogenous shrinkage from 530 to 35 µε. The optimized UHPC mixtures were cast as thin bonded overlays of 25, 38, and 50 mm (1, 1.5, and 2 in.) in thickness over pavement sections measuring 1 × 2.5 m² (10.7 x 27 ft²). Early-age and long-term deformation caused by concrete, humidity and temperature gradients, as well as cracking and delamination were monitored over time. Test results indicate that there was no surface cracking or delamination in UHPC overlays after more than 200 d of casting. After laboratory investigations, a life cycle cost analysis (LCCA) was determined for the selected concrete mixtures with different mixture compositions and performance characteristics. Results indicate that, based on both deterministic and probabilistic results, UHPC overlay with minimum 25 mm (1 in.) thickness is a more cost-effective option compared with other commonly used materials, such as latex-modified concrete and conventional bonded concrete overlays.

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Report number: cmr18-006
Published: April 2018
Project number: TR201704
Authors: Kamal H. Khayat and Mahdi Valipour
Performing organization: Missouri University of Science and Technology Department of Civil, Architectural and Environmental Engineering

Use of Lightweight Sand for Internal Curing to Improve Performance of Concrete Infrastructure

The project presented in this report aimed to develop an effective methodology to use saturated lightweight sand (LWS) for internal curing to enhance concrete performance and prolong service life of concrete structures. High-performance concrete (HPC) mixtures approved by MoDOT for pavement and bridge deck structures were used for the baseline mixtures. Five different types of saturated LWS employed at various contents were investigated to evaluate the optimum dosage of LWS and maximize its effectiveness on enhancing concrete performance. The content of LWS was varied to ensure the introduction of internal curing water that can secure up to 150% of the water consumed by chemical shrinkage during cement hydration (As per ASTM C1761). Performance improvement from the LWS focused mainly on reducing autogenous and drying shrinkage and the resulting cracking potential without sacrificing durability and cost competence. Proper combinations of internal and external curing were found to enhance shrinkage mitigation. Under 7 days of initial moisture curing, HPC made with the LWS3 resulted in the lowest overall shrinkage. The Bridge-LWS2-150% exhibited the best performance in mitigating autogenous shrinkage where the concrete maintained 160 micro-strain of expansion even after 175 days of age. The lowest drying shrinkage was obtained with the Bridge-LWS3-50% mixture (340 micro-strain) at 175 days subjected to 28 days of moist curing. For the paving HPC, the lowest drying shrinkage at 155 days was obtained with the Paving-LWS3-150% mixture (265 micro-strain) subjected to 28 days of moist curing. Concrete proportioned with the LWS2 expanded shale LWS exhibited the best compressive strength, regardless of the curing regime. In terms of initial moisture curing duration, the application of 7 days of moisture curing resulted in the highest compressive strength compared with other curing conditions. The 56-day compressive strength of HPC designated for bridge deck construction that was made with the LWS1 was up to 10 MPa (1,450 psi) greater than the Bridge-Reference concrete made without any LWS. The Bridge-LWS2-100% and Bridge-LWS1-50% mixtures exhibited the highest 56-day MOE of 42.5 GPa (6,615 ksi) under Standard curing. The Bridge-LWS3-100% mixture cured under Standard conditions had the highest 56-day flexural strength of 5.5 MPa (800 psi). The mixtures made with LWS2 presented the lowest sorptivity, regardless of the curing condition and LWS content. The findings from this comprehensive project provided a basis for: (1) new mixture design methodology and guidelines for using LWS for internal curing for bridge deck and pavement applications; and (2) validation of performance improvement when using internal curing and cost competitiveness in the State of Missouri.

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Report number: cmr18-005
Published: March 2018
Project number: TR201701

Authors: Kamal H. Khayat, Weina Meng, Mahdi Valipour and Matthew Hopkins

Performing organization: Missouri University of Science and Technology Department of Civil, Architectural and Environmental Engineering

Intelligent Compaction and Infrared Scanning Field Projects with Consulting Support

The Missouri Department of Transportation (MoDOT) was awarded a grant from the FHWA Accelerated Innovation Deployment (AID) program, in 2016. MoDOT provided the required matching funds to support this Intelligent Compaction (IC) and Infrared Scanning (IR) Field Projects with Consulting Support in 2017. The consulting support was provided by the Transtec Group (Consultant) and includes the development MoDOT IC-IR Protocol and training materials, conducting IC-IR training, on-site technical support to IC-IR field projects, data analysis, and reports of IC-IR field data. The original IC-IR project included 10 field projects.  Additional MoDOT funding was later added to support three additional IC-IR projects, making a total of 13 field projects. This document is the final report summarizing the two combined projects including field test results, lessons-learned and recommendations.

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Report number: cmr18-003
Published: February 2018
Project number: TR201716

Authors: George Chang, Kiran Mohanraj, and David Merritt (Transtec Group); Victor (Lee) Gallivan (Gallivan Consulting, Inc.)

Performing organization: The Transtec Group, Inc.

Evaluation of Automated Flagger Assistance Devices

Automated flagger assistance devices (AFADs) are designed to improve worker safety by replacing flaggers who are typically located near traffic approaching a work zone. In this study, a new AFAD developed by the Missouri Department of Transportation (MoDOT) was evaluated via a combined driving simulator and field study. The MoDOT AFAD configuration conformed to the Manual on Uniform Traffic Control Devices and involved STOP/SLOW paddles, red/yellow lights, and a changeable message sign (CMS). This AFAD was incorporated onto a truck-mounted attenuator for operator protection. Driver behavior measures, including approach speed, initial braking location, full stop distance, reaction time, and intervention rate, were used to measure the effectiveness of AFAD as compared to a human flagger. In the field study, the AFAD induced slower vehicle approach speeds (4.20 mph less), stopped vehicles farther back (11.4 feet), and released traffic quicker (1.3 seconds less) than flaggers. In the driving simulator study, the AFAD and its alternative designs significantly reduced average approach speeds (7.7 to 8.9 mph) and increased the distance at which the approaching vehicles came to a complete stop (24 to 48 feet). Both the field and the simulator study were followed by surveys that captured driver preferences and understanding. The results from both surveys showed that drivers understood AFADs well and preferred AFADs over human flaggers, especially for the MoDOT AFAD configuration. Overall, the AFAD has potential to improve the safety of work zones for both workers and the traveling public.

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An interim report cmr 17-010 was published for this project in August 2017.

Report number: cmr18-004
Published: February 2018
Project number: TR201717
Author(s): Henry Brown, Carlos Sun, Siyang Zhang and Zhu Qing
Performing organization: University of Missouri-Columbia

Economic Impact Study for Public Ports in Missouri

The Missouri Department of Transportation (MoDOT) commissioned this study to assess the economic role of public ports and waterways in supporting and enhancing the state and local economy. The key objectives of the study are to profile the economic activity of the public port facilities in Missouri; identify and assess port-dependent and port-benefitted industries in Missouri; and evaluate the economic impact of ports and waterways on the state in terms of employment, tax revenue, economic output, and induced or multiplier effects. The study team used a combination of port/shipper interviews, site visits, analysis of commodity flow data, and economic modeling to accomplish these goals. The results of the study provide insight to MoDOT and other stakeholders to inform future investment decisions for Missouri’s ports and waterways. See also separately published individual port brochures.

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Report number: cmr18-002
Published: February 2018
Project number: TR201711

Performing organizations: Cambridge Systematics, Inc. with Hanson Professional Services, Inc.

Missouri Highway Safety Manual Recalibration

The Highway Safety Manual (HSM) is a national manual for analyzing the highway safety of various facilities, including rural roads, urban arterials, freeways, and intersections. The HSM was first published in 2010, and a supplement was published in 2014 that addressed freeway interchanges. The HSM incorporated the safety modeling results from several National Cooperative Highway Research Projects that used data from various states across the nation. The HSM recommends that individual states calibrate the HSM to local conditions on a regular basis. An initial statewide calibration for Missouri was finalized in 2013. The current recalibration effort builds upon the previous calibration and keeps the calibration values up-to-date with the most current crash data and calibration methodology. The current effort also involves the development of crash severity distributions functions so that crash frequencies can be estimated according to the severities of fatal, severe injury, minor injury, and property damage only. HSM calibration is a labor intensive effort that requires the derivation and use of detailed data such as road geometrics, traffic volumes, traffic signalization, land-use, and crash frequency and severity. This report documents the details of the methodology employed for facility site selection, data collection, data processing, calibration, and severity assignment. A total of 16 facility types were calibrated. These include rural 2-lane segments with the related 3-leg and 4-leg intersections; rural multilane segments with the related 3-leg and 4-leg intersections; urban 2-, 4- and 5-lane arterial segments; urban and rural 4-lane and urban 6-lane freeway segments; urban 3- and 4-leg signalized intersections; and urban 3- and 4-leg unsignalized intersections. The calibration results indicated that the HSM predicted Missouri crashes reasonably well, with the exception of a few site types for which it may be desirable for Missouri to develop its own safety performance functions in the future.

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Report number: cmr18-001
Published: February 2018
Project number: TR201616
Author(s): Carlos Sun (PI), Praveen Edara (co-PI), Henry Brown (co-PI) with Jacob Berry, Boris Claros, and Xiang Yu (Research Assistants)

Performing organization: University of Missouri-Columbia, Department of Civil & Environmental Engineering