Zhongjie Zhang

Bio: Zhongjie Zhang is an academic researcher from Louisiana State University. The author has contributed to research in topics: Falling weight deflectometer & Pavement management. The author has an hindex of 15, co-authored 114 publications receiving 1187 citations. Previous affiliations of Zhongjie Zhang include Worcester Polytechnic Institute.

Statistical to Fuzzy Approach toward CPT Soil Classification

Abstract: A soil engineering classification derived from the cone penetration test (CPT) involves the uncertainty of correlation between soil composition and soil mechanical behavior. This uncertainty results in overlaps of different soil types in currently used CPT soil classification systems. Accordingly, two statistical soil classification criteria, region estimation and point estimation, are suggested to address this problem. Further, a new fuzzy subset approach is introduced to develop a truly independent CPT soil engineering classification, and to establish a transition between the new fuzzy approach and conventional soil classifications by utilizing local site- and project-specific calibrations. CPT results conducted at the National Geotechnical Experimentation Site at Texas A&M University are used to demonstrate this new CPT soil engineering classification methodology.

Application of Shakedown Theory in Characterizing Traditional and Recycled Pavement Base Materials

Abstract: To facilitate the use of recycled materials in pavement construction, a mechanistic-based approach is required to better characterize pavement base materials. This paper demonstrates the application of the shakedown theory to characterize the behavior of traditional and recycled base materials based on laboratory repeated load triaxial RLT tests and full-scaled accelerated loading tests. A new approach that is based on dissipated energy is proposed to explain different shakedown responses of tested materials under repeated loading. The dissipated energy approach illustrated that there are two responses during RLT tests, namely, stable and unstable responses, which are dependent on the loading levels and type of tested material. It was also observed that the transition from the stable to unstable response represents gradual microstructural adjustments of tested materials to accommodate the applied loading. This gradual transition explains the difficulties in identifying some material responses within the shakedown theory based only on the permanent strain rate criteria. Based on the results of this study, a mechanistic-based design procedure to incorporate various recycled materials into pavement bases is recommended.

Durability of Cement Stabilized Low Plasticity Soils

Abstract: Three testing methods for predicting the durability of cement-stabilized soils—the tube suction (TS), 7-day unconfined compression strength (UCS), and wetting–drying durability tests—were tested and compared for their correlations and influence factors using a problematic low plastic silt clay from subgrade commonly encountered in Louisiana. A series of samples was molded at six different cement dosages (2.5, 4.5, 6.5, 8.5, 10.5, and 12.5% by dry weight of the soil) and four different molding moisture contents (15.5, 18.5, 21.5, and 24.5%). The test results indicate that the water–cement ratio of cement-stabilized soil had the dominant influence on the maximum dielectric value (DV), 7-day UCS, and durability of stabilized samples tested, although the dry unit weight of cement-stabilized soil could cause the variation of the results. This study confirms that TS, 7-day UCS, and wetting-drying durability tests are equivalent in predicting durability, and tentative charts to ensuring the durability of cement-...

Pavement Structures Damage Caused by Hurricane Katrina Flooding

Abstract: In September of 2005, Hurricane Katrina devastated New Orleans and caused sustained flooding. Limited pre- and postflooding tests indicated that the pavement structures tested were adversely impacted by the flood water. Consequently, the Louisiana Dept. of Transportation and Development hired an independent contractor to structurally test approximately 383 km ( 238 mi ) of the region’s federally aided urban highway system both inside and outside of the flooding area. Falling weight deflectometer (FWD) tests were performed every 161 m ( 0.1 mi ) over each selected roadway, along with other field tests. The FWD data were imported into a geographical information system and plotted against a USGS geo-referenced map. Comparative analyses were made possible through the use of extensive flood maps made available through NOAA and FEMA. This arrangement made it possible to classify spatially and graphically all test points on the basis of flooding versus nonflooding, short flooding duration versus longer flooding ...

Mitigation strategies for reflection cracking in rehabilitated pavements – A synthesis

Abstract: The placement of an asphalt overlay on top of an existing pavement is rarely a lasting solution. Due to continuous movement of the existing pavement, existing discontinuities such as cracks and joints propagate through the overlay causing reflection cracking. Reflection cracking is a serious challenge associated with pavement rehabilitation. Practical experience shows that reflection cracking propagates at a rate of 1 in. per year. As the need grows for new rehabilitation methodologies to improve the performance of overlays against reflection cracking, a number of state transportation agencies tasked the authors of this paper to conduct a comprehensive review of treatment methods available to delay or to prevent reflection cracking in rehabilitated pavements and to survey current state of practice in addressing this distress. Based on the results of the literature review and the survey questionnaire, a summarized assessment is presented for each treatment method. Further, a number of treatment methods were identified for further evaluation by the state transportation agencies. For existing HMA pavements, crack sealing and overlay, chip.

American Society for Testing and Materials

Abstract: The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

Interpretation of cone penetration tests — a unified approach

Abstract: The electric cone penetration test (CPT) has been in use for over 40 years and is growing in popularity in North America. This paper provides some recent updates on the interpretation of some key g...

Experimental feasibility study of geopolymer as the next-generation soil stabilizer

Abstract: In many civil engineering constructions, soft and weak soils are often stabilized with ordinary Portland cement (OPC) and lime. The production processes of traditional stabilizers are energy intensive and emit a large quantity of CO2. Geopolymer, with its high strength, low cost, low energy consumption and CO2 emissions during synthesis, offers a promising alternative to OPC. In this study, a lean clay was stabilized with metakaolin based geopolymer at different concentration (ranging from 3 to 15 wt.% of unstabilized soil at its optimum water content) to examine the feasibility of geopolymer in stabilizing soils. Geopolymer stabilized soil specimens were characterized with compressive strength testing, volume measurements during curing, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The testing results indicated that with geopolymer concentrations, compressive strength, failure strain and Young’s modulus of the stabilized soil specimens increased, and shrinkage strains during curing decreased. The microstructural analyses confirmed the formation of geopolymer gels in the stabilized soil, and showed the soil tended to form more homogeneous and compact microstructures after stabilization. This study illustrated that metakaolin based geopolymer can be an effective soil stabilizer for clayey soils. Further studies on the long-term performance of geopolymer stabilized soils, the use of geopolymers synthesized from industrial wastes, and the financial and environmental cost of applying geopolymer in soil stabilization are worth being conducted.

Characterization of Cementitiously Stabilized Layers for Use in Pavement Design and Analysis

Abstract: This report presents information on the characterization of cementitiously stabilized layers and the properties that influence pavement performance. It also contains recommended performance-related procedures for characterizing these layers and performance-prediction models for incorporation into the mechanistic–empirical pavement analysis methods. Individual chapters highlight pavement distresses of hot-mix asphalt pavements and concrete pavements, laboratory tests and model development, and model calibration. The material contained in the report will be of immediate interest to state materials, pavement, and construction engineers and others involved in the different aspects of pavement design and construction.

A state-of-the-art review of parameters influencing measurement and modeling of skid resistance of asphalt pavements

Abstract: A state-of-the-art review of key parameters that influence measurement and modeling of skid resistance of asphalt pavements is provided. Tire-pavement interaction/friction is discussed and the current harmonization method of friction measurements questioned. The latest developments on pavement surface texture measurement and characterization are highlighted. A critical review of aggregate properties affecting friction, the frictional properties of asphalt mixtures and the influence of environmental factors on skid resistance is presented. An overview of modeling efforts entailing different aspects of tire-pavement friction is also presented. The frictional performance of asphalt pavements largely depends on the type and quality of coarse aggregates used. The different hot mix asphalt (HMA) classifications generally have similar microtextures. Their frictional performance follows the same order as their macrotextures. There is need for experimentally-validated skid resistance prediction models, especially for warm surfaces. Such models should account for tire and pavement surface texture characteristics, and the influence of environmental factors. Some other research needs are also identified.