Deren Yuan

Nondestructive Testing to Identify Concrete Bridge Deck Deterioration

This work was sponsored by the Federal Highway Administration in cooperation with the American Association of State Highway and Transportation Officials. It was conducted in the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies. The project was managed by Monica Starnes, Senior Program Officer for SHRP 2 Renewal. The research reported herein was performed by the Center for Advanced Infrastructure and Transportation (CAIT) at Rutgers University (RU); the Center for Transportation Infrastructure Systems (CTIS) at The University of Texas at El Paso (UTEP); the Federal Institute for Materials Research and Testing (BAM), Germany; and Radar Systems International, Inc. (RSI). Rutgers University was the coordinator and contractor for this project. Dr. Nenad Gucunski, professor and chair of Civil and Environmental Engineering and director of CAIT’s Infrastructure Condition Monitoring Program at RU, was the principal investigator. The other authors of this report are Dr. Soheil Nazarian, professor of Civil Engineering and director of CTIS at UTEP; Dr. Deren Yuan, research associate at CTIS at UTEP; Dr. Herbert Wiggenhauser, head of Non-Destructive Testing (NDT) in Civil Engineering at BAM; Dr. Alexander Taffe, leader of Combination and Automation of NDT of Buildings at BAM; Dr. Parisa Shokouhi, Alexander von Humboldt Research Fellow, hosted by BAM; and Doria Kutrubes, president of RSI. Arezoo Imani and Touraj Tayebi, graduate research assistants at RU, helped conduct the validation testing, data analysis, and web manual content preparation. Hoda Azari, a graduate research assistant, and Dr. Manuel Celaya, a research engineer at UTEP, assisted in the validation study as well. Hooman Parvardeh, research assistant at RU, helped build the reference database and develop the framework for the web manual, while Erica Erlanger, a research staff member at RU, edited the manuscript. Their contributions are gratefully acknowledged. The research team also gratefully acknowledges contributions of the participants from industry and academia in the validation testing. The participants include NDT Corporation; Germann Instruments; Olson Engineering; Dr. Ralf Arndt, National Research Council associate at FHWA Turner–Fairbank Highway Research Center; Ingegneria Dei Sistemi S.p.A. (IDS), Italy; 3D-RADAR, Norway; Dr. John Popovics, University of Illinois at Urbana-Champaign; Dr. Jinying Zhu, The University of Texas at Austin; Rutgers University—Center for Advanced Infrastructure and Transportation; and The University of Texas at El Paso—Center for Transportation Infrastructure Systems. The contributions of these participants were critical for the evaluation and grading of the performance of NDT technologies.

Structural Field Testing of Flexible Pavement Layers with Seismic Methods for Quality Control

Current mechanistic procedures for structural design of flexible pavements consider the modulus and Poisson’s ratio of each layer. Unfortunately, the construction specifications are not based on these engineering properties. The acceptance criteria typically are based on adequate density of the placed and compacted materials. To successfully implement any mechanistic pavement design procedure, and to move toward performance-based specifications, it is essential to develop tools that can measure the modulus and Poisson’s ratio of each layer. Presented is an approach to such a program based on seismic testing. Field protocols and test equipment, which in a rational manner combine the results from laboratory and field tests with those used for quality control during construction, are discussed. A series of simplified laboratory tests that are compatible with the field tests also can be used; these methods are discussed. Several case studies are included to present some results that can be obtained with the methodology. Several issues that remain to be addressed are included.

Quality Assessment and Quality Control of Deep Soil Mixing Construction for Stabilizing Expansive Subsoils

This paper presents the process and results of a quality management program performed during and immediately after the construction of two deep soil mixing (DSM) test sections. The quality management program consisted of laboratory, in situ, and mineralogical tests to address the effectiveness of the treatment during and after construction. In situ investigations including the down-hole seismic and spectral analysis of surface waves (SASW) test methods were performed to evaluate the degree of improvement achieved through the measurement of compression and shear-wave velocities of the columns and surrounding soils. Scanning electron microscopy and electron dispersive x-ray analysis were performed on raw, laboratory treated and field-treated specimens for qualitative understanding of the degree of mixing achieved in the field and the compounds formed at particle level during stabilization, respectively. Laboratory tests results on field cores indicated that both field stiffness and strength are about 20 to 40% less than the corresponding laboratory prepared soil samples. The down-hole seismic and SASW tests showed considerable improvement in stiffness in and around the DSM columns. Mineralogical studies indicated the formation of silica and alumina hydrates along with interwoven structure of lime-cement treated clay particles in both laboratory and field specimens, suggesting adequate mixing of the soil and binder in both environments.

Variation in Moduli of Base and Subgrade with Moisture

The modulus of each layer in a pavement system is one of the primary parameters that affect the performance of the pavement. The determination of the layer moduli under different moisture regimes is an essential task in any pavement design. Seismic nondestructive testing technology based on the use of stress waves has been shown to be a useful tool in achieving this goal. Based on these studies, laboratory tests have been developed to quantify the moisture susceptibility of base and subgrade materials. These suggested methods are also described.

A Simple Method for Determining Modulus of Base and Subgrade Materials

This paper describes how the resilient modulus test is commonly used for determining the modulus of base or subgrade materials as well as to establish their nonlinear behavior. Since the resilient modulus test is time consuming, the number of tests performed for a given project is limited. For day-to-day operation of highway agencies, a more rapid test method is needed. The stress wave (or seismic) method is being considered in Texas for this purpose. Seismic methods of testing can rapidly and nondestructively provide fundamentally correct moduli at know states of stress. Unlike the resilient modulus test, comparative field testing methods are available for seismic methods that can provide similar results under similar conditions. The paper describes the seismic test procedure and its relationship to the resilient modulus test results. Also discussed are the repeatability and reproducibility of the results as a function of operator experience, type of soil, and preparation method.

Relating laboratory and field moduli of texas base materials

Resilient modulus of base is an important parameter in the AASHTO pavement design method. However, the manner to determine this parameter is not well defined. Recent efforts in combining the resilient moduli from laboratory testing with those obtained in the field using nondestructive testing devices are presented. Laboratory tests were carried out in two stages. In the first stage, virgin materials from the quarry compacted to optimum moisture content were tested. In the second stage, similar base materials were retrieved from in-service roads. Specimens were prepared and tested at the corresponding field densities and moisture contents. Nondestructive tests were performed with the Falling Weight Deflectometer and the Seismic Pavement Analyzer. Based on tests on 10 different base materials from different parts of Texas, it was concluded that it may be difficult to directly compare moduli from laboratory and field tests; however, they can be combined for effective pavement design.

Evaluation and Mix Design of Cement-Treated Base Materials with High Content of Reclaimed Asphalt Pavement

Reclaimed asphalt pavement (RAP) and granular base materials were collected from stockpiles throughout Texas to evaluate the feasibility of using mixes containing high RAP content for base course applications. Mixes containing 100%, 75%, and 50% RAP treated with 0%, 2%, 4%, and 6% of portland cement were evaluated in a full-factorial laboratory experiment. For mixes of 75% and 50% RAP, both virgin and salvage base materials were used. Experimental results indicated that besides the cement content, the RAP content and finer aggregate content significantly affected the properties of the RAP mixes, but the effects of RAP type and asphalt content in RAP were limited. To achieve a 300-psi unconfined compressive strength as required by the Texas Department of Transportation, the optimum cement contents were statistically about 4%, 3%, and 2% for mixes of 100%, 75%, and 50% RAP, respectively. Because the achievement of any specified strength or stiffness might not always ensure the durability of a mix, other parameters that might be relevant to performance and long-term durability were evaluated through laboratory testing. These parameters included modulus, indirect tensile strength, and moisture susceptibility as well as cement leaching.

Mapping Voids, Debonding, Delaminations, Moisture, and Other Defects Behind or Within Tunnel Linings

Periodic monitoring of tunnel conditions and deterioration rates is the answer to determining the appropriate schedule of maintenance or rehabilitation activities to remedy structural problems that could lead to rapid deterioration and unexpected tunnel failures. The aggressive environmental conditions in which tunnels exist, as well as the need to keep tunnels open to traffic, make their inspection a challenge. Nondestructive testingmethods that are automated, quantitative, and rapid, and that provide complete coverage compared with conventional visual inspections, could solve this dilemma. This report presents the findings of the Strategic Highway Research Program 2 (SHRP 2) Renewal Project R06G—High-Speed Nondestructive Testing Methods for Mapping Voids, Debonding, Delaminations, Moisture, and Other Defects Behind or Within Tunnel Linings. The study was divided into two phases to (1) establish testing criteria and prioritize the techniques to be developed and evaluated under the project on the basis of tunnel operators’ requirements and (2) conduct the necessary technology development for those techniques recommended. In addition to conducting technology development, the project performed proof-of-concept and field testing. Beyond this report, the deliverables for this project include two products that will be published separately: 1) a user’s manual, which provides information on three NDT technologies for inspection of tunnels; and 2) a brief manual to the analysis software Tunnelcheck, which was developed under this project.

USE OF INSTRUMENTED DYNAMIC CONE PENETROMETER IN PAVEMENT CHARACTERIZATION

The dynamic cone penetrometer data has been conventionally used for estimating the base and subgrade California bearing ratio. In recent years, a need for developing mechanistic pavement designs procedures has been emphasized. However, to develop mechanistic pavement design procedures, measuring engineering properties of parameter layers is essential. Two modifications to the existing dynamic cone penetrometer have been proposed in this paper for obtaining engineering properties of pavement layers. First, an ordinary dynamic cone penetrometer was instrumented with a load cell and an accelerometer to determine the energy imparted to the ground, the resistance to the penetration, and the penetration of the device into the base and subgrade. A second device consisting of a three-dimensional accelerometer embedded in a DCP-like rod was developed to measure modulus and Poissons ratio of the base and subgrade layers. This device can be placed in the same hole drilled for the first device, thus requiring minimum coring.

Use of Seismic Pavement Analyzer To Monitor Degradation of Flexible Pavements Under Texas Mobile Load Simulator

The seismic pavement analyzer (SPA) combines several wave propagation techniques in a single unit and can rapidly perform nondestructive tests to determine the condition of pavement. The modulus of each layer of pavements is a major parameter estimated with the SPA. The SPA and its portable version, the PSPA, have been used with the field operation of the Texas mobile load simulator (TxMLS) to detect the variation in properties of different layers with the number of axle loads applied to the pavement. The theoretical background related to the methods used with the SPA and PSPA is discussed. Results from tests of the SPA and PSPA at a TxMLS testing site are presented. The variation in moduli as a function of the deterioration of pavement is detected. The results have been compared with those obtained from direct seismic measurements made on the top of each layer to evaluate the accuracy of the devices. In general, a good agreement was achieved.