Author: Publisher: ISBN: Category : Subgrade Languages : en Pages : 76
Book Description
The impact hammer compaction has historically been used to develop moisture-density curves and fabricate specimens for strength testing for flexible base and subgrade materials. However, the precision of compressive strength results by the impact hammer compaction remains a concern that can result in conflicting test results on whether a material meets specification requirements. This project used the Superpave Gyratory Compactor (SGC) to analyze if SGC compaction enables improved precision of compressive strength tests for flexible base and subgrade materials and analyzed a procedure for determining the moisture-density curve of base and subgrade materials using the SGC. Also, the applicability of SGC for base materials was evaluated in context of mechanistic-empirical (M-E) pavement design methods. The results showed that SGC compaction produced compressive strength results with less variability and improved precision compared to impact hammer compaction. Also, from the measurement of M-E properties, base materials compacted with the SGC were associated with lower permanent strain and higher resilient modulus than the materials with the impact hammer. The evaluation of internal structure using X-ray Compute Tomography and Aggregate Image Measurement System helped explain the behavior ofmaterials compacted with both impact hammer and SGC compaction methods.
Author: Erol Tutumluer Publisher: CRC Press ISBN: 0203865286 Category : Technology & Engineering Languages : en Pages : 1560
Book Description
Bearing Capacity of Roads, Railways and Airfields focuses on issues pertaining to the bearing capacity of highway and airfield pavements and railroad track structures and provided a forum to promote efficient design, construction and maintenance of the transportation infrastructure. The collection of papers from the Eighth International Conference
Author: Ibrahim Karaman Publisher: Springer ISBN: 3319487663 Category : Technology & Engineering Languages : en Pages : 532
Book Description
This is a collection of papers presented at The TMS Middle East - Mediterranean Materials Congress on Energy and Infrastructure Systems (MEMA 2015), a conference organized by The Minerals, Metals & Materials Society (TMS) and held in Doha, Qatar. The event focused on new materials research and development in applications of interest for Qatar and the entire Middle East and Mediterranean region. The papers in this collection are divided into five sections: (1) Sustainable Infrastructure Materials; (2) Computational Materials Design; (3) Materials for Energy Conversion and Storage; (4) Lightweight and High Performance Materials; and (5) Materials for Energy Extraction and Storage: Shape Memory Alloys.
Author: Ronald J. Cominsky Publisher: National Research Council ISBN: Category : Transportation Languages : en Pages : 140
Book Description
This report summarizes the research devoted to three key aspects of the Superpave Level I mix design: volumetric mix design criteria for aggregates and mixes; compaction; and mix conditioning. The first chapter describes the Delphi group process that was used to select aggregate properties and specification values included in the Level I mix design procedure. Chapter 2 addresses the rationale for the selection of the gyratory compactor, its relations to field control, and validation. The final chapter summarizes the research associated with the development and validation of laboratory conditioning procedures for asphalt concrete mixes. It describes the procedures used to simulate both short- and long-term aging, as well as moisture sensitivity under repeated loading.
Author: Stephen Alan Cross Publisher: ISBN: Category : Aggregates (Building materials) Languages : en Pages : 66
Book Description
There is evidence that some Kansas mixes, which have performed well in the past, will not meet the currently proposed design requirements for a Superpave level I mix. The major problem is low voids in the mineral aggregate (VMA). The major reasons for low VMA are the high amounts of natural sand currently used and the higher compactive effort required by Superpave compared to 50-blow Marshall compaction. Cores, plant produced (field) mix, the original aggregates and asphalt cement were obtained from four low volume pavements. The cores established the in-place density of the pavements. The field mix was compacted in the Superpave Gyratory Compactor (SGC) to establish the number of gyrations required to reach the field density of the mix. The aggregates and asphalt cement were obtained and Superpave mix designs were performed. The void properties were evaluated at the original and revised Ndesign gyrations. The effect of reducing the ram pressure from 600 kPa to 400 kPa was evaluated as well.
Author: KD. Hall Publisher: ISBN: Category : Hot-mix asphalt Languages : en Pages : 13
Book Description
The Superpave gyratory compactor (SGC) is the "centerpiece" of the Superpave system. Hot-mix asphalt (HMA) specimens are compacted in the laboratory using the SGC through the application of pressure and an applied angle of gyration. The original compaction specification for the SGC requires the angle of gyration to be 22°±0.35 mrad (1.25±0.02 deg), measured externally to the compaction mold. Due to concerns regarding the inability of different compactors to produce HMA specimens with similar density, the Dynamic Angle Validation (DAV) kit was developed to measure the angle of gyration internally, or inside the mold. The DAV requires the use of HMA for the internal angle determination; logistical concerns and other issues led to the introduction of devices--the Rapid Angle Measurement (RAM) and the Hot-Mix Simulator (HMS)--which mechanically simulate the load placed on the SGC by the mix being compacted. This paper presents a summary of the state-of-the-practice concerning the internal angle of gyration and addresses potential strategies for implementing an internal angle specification into routine Superpave mixture design and quality control practices.
Author: 
Author: R. Michael Anderson
Author: Waterways Experiment Station (U.S.)
Author: Erol Tutumluer
Author: Ibrahim Karaman
Author: Ronald J. Cominsky
Author: Stephen Alan Cross
Author: KD. Hall
Author: Salma S. Tawfiq
Author: