Civil & Environmental Engineering
Asphalt, Geotechnical, and Aggregate Labs
Most of the typical aggregate testing can be completed such as gradation, LA abrasion, potential ASR reactivity, freeze-thaw durability, flat and elongation, absorption, specific gravity, voids content, and unit weight. The BCEL has a designated aggregate room for sieving and LA abrasion. Chemical testing can also be conducted on the aggregate. The OSU CIVE research team also has the abilities to test aggregates for mechanical responses such as California Bearing Ratio (CBR), Triaxial Shear Strength, Resilient Modulus (MR) and Permanent Deformation Accumulation under Repeated loading. The team can test cylindrical triaxial specimens with a diameter of 152 mm (6 in.) and a height of 305 mm (12 in.). These triaxial tests can be conducted with complete pore-water pressure control. Moreover, the set-up can also measure the permeability during the triaxial testing.
The OSU CIVE department as the ability to perform complete mechanical characterization (at different temperatures) of Asphalt Concrete. Currently available test equipment include:
- Asphalt Pavement Analyzer Jr. (APA, Jr.) capable of performing rut testing on both highway and airfield asphalt mixes;
- Asphalt Mix Performance Tester (AMPT Pro) to conduct tests such as Dynamic Modulus, Flow Number, and Flow Time
- Test Set-up to assess the cracking performance of asphalt mixes at intermediate temperatures (e.g. tests such as I-FIT, IDEAL CT, NFLEX, etc.)
Additionally, the basic equipment such as gyratory compactors, and those required for carrying out Superpave mix design and all related volumetric tests are available at the OSU laboratories.
The geotechnical engineering laboratories at OSU CIVE has all required equipment for complete mechanical, chemical, and hydraulic characterization of fine- and coarse-grained soils. Dr. Rifat Bulut and Dr. Deb Mishra collaborate to maintain the geotechnical engineering research laboratory at OSU CIVE. The test equipment available, can perform all types of geotechnical problems under saturated as well as unsaturated conditions. Some of the most significant equipment include:
- Multiple triaxial stress-path load frames with full control over pore water pressure;
- Multiple direct shear testing devices, and automatic soil consolidations systems
- Ability to measure unsaturated soil moisture diffusivity coefficient using thermocouple psychrometers;
- Fredlund Soil Water Characteristic Curve (SWCC) construction equipment;
- Soil swelling and shrinkage testing equipment
- Ring testing equipment for measuring tensile stresses in unsaturated soils
- Equipment to measure soil suction using different methods
Additionally, the group also has multiple Light Weight Deflectometers (LWDs), a Soil Stiffness Gauge, and a PANDA Penetrometer Device for in-situ modulus measurement on soil and aggregate layers. These devices are currently being used by Dr. Deb Mishra in a research project aimed at developing new deflection-based compaction specifications for open-graded base courses. Other equipment in the geotechnical laboratories include the complete test set-ups required for establishing commonly used mechanical and index properties, moisture-density characteristics, etc.
Numerical Modeling Capabilities
The OSU CIVE team has expertise in the use of several state-of-the art numerical modeling software packages. Some of the most commonly used software packages include:
- ABAQUS for Finite Element Modeling of structures, embankments, pavements, and railroad tracks
- Particle Flow Code (PFC) for Discrete Element (DE) Modeling of coarse-grained geomaterial behavior. Example applications include: (a) interaction between aggregates and geogrids in pavement and railroad applications; (2) studying the mechanism of particle breakage under repeated loading, etc.;
- Fast Lagrangian Analysis of Continua (FLAC; both 2D and 3D versions) for geotechnical analysis of soils, rocks, groundwater, and construction processes such as excavation.
For many construction materials there has been extensive nondestructive testing capabilities for both laboratory and field application. This nondestructive testing can be found in many forms throughout the laboratory depending on the research project. While NDT strength testing capabilities of rebound test, penetration test, pull-out test, and break-off test can be found in many material laboratories, the BCEL also has ultrasonic pulse velocity devices with 54 kHz and 150 kHz P-wave transducers and 250 kHz S-wave transducers to enable estimation of dynamic modulus of elasticity of materials. These ultrasonic pulse velocity devices have been used to not only determine the uniformity of a concrete structure, but monitor the crack development with a concrete sample being loaded. The BCEL also has the ability to complete acoustic emission testing. This is where high resolution microphones are used to detect cracks within materials as they occur.
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