Evaluation of Constructed, Cast-in-Place (CIP) Piling Properties

Sponsor: Wisconsin Department of Transportation

PI: Devin Harris

Closed-end, round, cast-in-place (CIP) tubular friction piles are commonly used in bridge and retaining wall structures in the State of Wisconsin. Installation of CIP piles is typically performed by the contractor according to specified bearing capacities in the construction plans. These CIP piles have historically been installed at depths ranging from 30 ft. to 120 ft., with nominal diameters between 10-3/4 in. and 14 in. and shell thicknesses between 1/4 in. and 3/8 in.

In this study, a series of field-cast piles are investigated both experimentally and numerically to assess their structural capacity. The evaluation consisted of testing stub sections of pile with varying diameters (10-3/4 in., 12-3/4 in.), wall thicknesses (0.375 in., 0.5 in.) under various states of stress. The focus was on the axial capacity, the bond capacity and the compressive strength of the core material.

A copy of this report can be found on the Wisconsin Department of Transportation website.

 

Reduction of Minimum Required Weight of Cementitious Materials in WisDOT Concrete Mixes

Sponsor: Wisconsin Department of Transportation

PI: Lawrence Sutter

This project was designed to explore the feasibility of lowering the cementitious materials content (CMC) used in Wisconsin concrete pavement construction. The cementitious materials studied included portland cement, fly ash, and ground granulated blast furnace slag. For the first phase, mixtures were prepared using the current WisDOT aggregate grading specification. For the second phase, mixtures were prepared using an optimized (e.g. Shilstone) gradation. A variety of tests for fresh and hardened concrete were conducted to determine the viability of low CMC mixtures for use in concrete pavement.

The research resulted in several successful low CMC concrete mixtures in terms of workability, strength, and durability. Many unsuccessful low CMC concrete mixtures were also produced. The analysis of the data suggests a practical minimum CMC of 5.0 sacks/yd³ for concrete. However, successful mixtures containing fly ash were achieved at the CMC levels of 4.0 sacks/yd³ and 4.5 sacks/yd³ . The same minimum CMC limits were established in both the first and second phases of the research, regardless of the change in aggregate gradation.

Lawrence Sutter
Lawrence Sutter

Laboratory Study for Comparison of Class C Versus Class F Fly Ash for Concrete Pavement

SPONSOR:  WISCONSIN DEPARTMENT OF TRANSPORTATION (WISDOT)

PI: Lawrence Sutter

Photo by Alibaba.com

The two objectives of this research were to a) evaluate Class F and Class C fly ash sources for use in paving concrete and b) determine acceptable proportions of each ash type to use in paving mixtures. A combined study was performed involving characterization with respect to AEA adsorption using the foam index test, direct measurement of adsorption, and the iodine number test and a partial factorial experiment was conducted to evaluate concrete mixtures prepared using different fly ash, cement, and aggregate sources. The adsorption testing highlighted known inconsistencies of loss on ignition measurements. Freeze-thaw testing in 4% CaCl2 solutions indicated no statistical difference in performance with or without fly ash but fly ash type was a significant factor in mixtures that failed freeze-thaw testing. Compressive and flexural strength followed the classical behavior expected of fly ash mixtures. Maturity showed the largest impact of fly ash addition. Overall the Class F and Class C ash sources performed well and using either at substitution levels up to 30% is recommended. Additional scrutiny of some Class F sources, with respect to freeze-thaw performance, is warranted. Use at higher levels should be done only after performance testing of the specific combination of materials to be used at the job-mix proportions.

A copy of this report can be found on the Wisconsin Department of Transportation website.

Lawrence Sutter
Lawrence Sutter

Identifying Cost and Funding Alternatives for Equipping Operating While Intoxicated Offenders with Ignition Interlock Devices

Sponsor:  Wisconsin Department of Transportation

PI:  John Hill

Ignition Interlock Devices (IID) have been used in multiple states to deter repeat operating while intoxicated (OWI) offenders from further offenses.  It has been found in the state of California that a group of offenders who had an order to use an IID had a reduction in future crash rates of 24 percent, while slight changes were seen in those that were not ordered the use of an IID.  Those drivers who installed the IID also had a lower rate of future DUI convictions.   A major issue with IIDs has been compliance.  Studies have shown that as few as 10% of drivers convicted of OWI and ordered to install an IID device, actually do so.

Research Objectives
– Identify and characterize OWI offenders in Wisconsin  and develop a 10 year forecast of overall
OWI arrests and arrests of particular high risk offenders.
– Estimate IID implementation costs based on the forecast model developed and determine the
overall affordability of IID devices for OWI offenders
– Identify potential funding sources to increase IID installations.

Methodology
Information regarding over 200,000 OWI offenders in Wisconsin from 2005-2009 was analyzed.  Using a logistic regression model, characteristics of OWI offenders who were likely to repeat the offense within 1 or 2 years were identified.  Additionally, a 10 year forecast model was developed which was based on annual historical arrest levels over the past 20 years, as well as monthly vehicle miles travelled an d economic data over the past 5 years.  Using this information, along with cost data collected from interviewing IID manufacturers, the overall cost to equip the vehicles of future OWI offenders was collected.  Income levels of IID offenders were also modeled using an exponential distribution to determine what proportion of offenders may be unable to afford an IID.  Finally, an analysis of potential funding sources was conducted to determine if supplementing the cost of IIDs might be a feasible means of increasing IID order compliance.