Aggregate and Petrographic Laboratory Overview
The Aggregate and Petrographic Laboratory (APL) at the Turner-Fairbank Highway Research Center (TFHRC) provides facilities for the evaluation, preparation, and testing of aggregate sources, products, and samples for use in concrete, asphalt mixtures, and granular base course applications. Staffed by an experienced geologist and petrographer, the APL is able to conduct research, work with other TFHRC laboratories in characterizing research materials and deterioration mechanisms, and assist in forensic evaluations of construction materials for others within Federal Highway Administration (FHWA) and with State departments of transportation (DOTs).
Facilities are available for characterizing highway materials using mechanical and durability tests, identification and quality testing of mineral aggregates, and troubleshooting of inferior quality materials or distress in concrete using forensic petrography. The Petrography Laboratory includes state-of-the-art transmitted and reflected light compound and reflected light microscopes and image-capturing tools, along with air-void parameter assessment using an American Society for Testing and Materials (ASTM) C 457 test method for hardened air-entrained concrete. When necessary, the APL collaborates with the Chemistry Laboratory, which is equipped with wet, analytical, and spectroscopic chemical methods. Included in the Chemistry Laboratory are an Analytical/Spectroscopy Laboratory, a Materials Characterization Laboratory, and modern x-ray diffraction (XRD) and scanning electron microscopy (SEM) tools, along with laboratories for conducting bench scale research.
Recent Accomplishments and Contributions
- Mengesha A. Beyene, Jose F. Munoz, Richard C. Meininger, and Carmelo Di Bella,“Effect of Internal Curing as Mitigation to Minimize Alkali-Silica Reaction Damage”, ACI Material Journal, May/June 2017.
- Mengesha A. Beyene, Richard C. Meininger, Nelson H. Gibson, Jose F. Munoz & Jack Youtcheff, “Forensic investigation of the cause(s) of slippery ultra-thin bonded wearing course of an asphalt pavement: influence of aggregate mineralogical compositions”, International Journal of Pavement Engineering, V17, Issue 10. 2016.
- Tanesi, Jussara, Bentz, Dale P, Jones, Scott Z, Mengesha, Beyene, Kim, Haejin, Ardani, Ahmad, Arnold, Joshua, and Stutzman, Paul E, “Influence of Aggregate Properties on Concrete Mechanical Performance”, Transportation Research Board, 96th Annual Meeting, Publication 2017, Washington, D.C.
- Tanesi, J., Kim, H., Beyene, M., and Ardani, A., “Super Air Meter for Assessing Air-Void System of Fresh Concrete”, Advances in Civil Engineering Materials, Vol.5, No. 2, 2016, pp. 22-37.
- Jussara Tanesi, Haejin Kim, Mengesha Beyene, A. Ardani, “Super Air Meter for Assessing Air-Void System of Fresh Concrete”, Conference paper, 2015 TRB Annual meeting.
- Muzenski, Scott W, Flores-Vivian, Ismael, Beyene, Mengesha A, and Sobolev, Konstantin “Performance of Fiber/Reinforced Composites with Nano-particle-based Polymethyl Hydrosiloxane Emulsions”, 13P., TRB 93rd Annual Meeting Compendium of Papers, 2014.
- J.F. Muñoz, C. Balachandran, Y. Yao, A. Shastry, L. Perry, M. Beyene, and T. Arnold, “Forensic investigation of the cause(s) of slippery ultra-thin bonded wearing course of an asphalt pavement: influence of binder content”, International Journal of Pavement Engineering. July 2016. DOI: 10.1080/10298436.2016.1199870.
- Petrographic Methods of Examining Hardened Concrete: A Petrographic Manual, FHWA-HRT-04-150, July 2006
- Examination of ultra-thin bonded wearing course (UTBWC) related to surface skid resistance problems on asphalt surfaced pavement.
- Provided a chapter on petrography for an American Concrete Institute (ACI) document on “Advanced analysis techniques for hardened cement pastes and concretes”.
- Examination of concrete bridge pier deterioration.
- Petrographic examination of autoclaved concrete specimens from a proposed accelerated test for alkali-silica reactivity (ASR).
- Carbonation study of a concrete prism made with an alternative cementitious material (ACM) consisting of a calcium silicate cement that reacts with carbon dioxide supplied during curing.
- Analysis of grout mixtures to determine the reactive components versus the inert materials.
- Forensic petrographic analyses of concrete in several aging bridges.
- Investigation of sidewalk scaling due to winter deicing/salt exposure following a winter with above-average snowfall.
- Aggregate-paste interfacial transition zone (ITZ) study of concrete mixes with different aggregate types.
- Examination of suspected alkali carbonate reaction (ACR) in deteriorating concrete pavement.
- Characterization of aggregate-paste interfaces of broken concrete specimens.
- Assessment of the concrete air void system of bridge deck cores.
- Petrographic examination of concrete blocks to identify aggregate constituents.
- Testing and analyses of concrete cores from two bridges.
- Examination of calcium silicate cement powdered ACM binders made in two different cement kilns with different raw materials.
- Petrographic analysis of coarse and fine aggregate.
- Air-void analyses of hardened air-entrained concrete.
- Forensic petrographic analyses of concrete cores from concrete pavement with low strength because of unstable coarse aggregate materials.
- Brief report on paste analysis of geopolymer concrete sample.
- Petrography of aggregates used for TFHRC Chemistry Lab ASR research.
- Detailed stereomicroscope observation of asphalt cores for several forensic studies.
- Petrographic evaluation of seal coat aggregate material.
- Characterization of reference ACR aggregate in Pittsburg, Ontario.
- Evaluating marginal aggregates for use in concrete, such as ACR and ASR aggregates.
- Determination of aggregate rock types and mineralogical compositions. Some examples are shown below:
|Aggregate Rock Type||Mineralogical Compositions|
|Natural Sand||Quartz with lesser amounts of quartzite/strained quartz and chert and minor amounts of fine and coarse-grained ferruginous sandstone, granitic rock, and feldspar.|
|Gravel||Quartz, quartzite, chert/chalcedonic chert, with lesser amount of sandstone.|
|Limestone||Fine-grained micritic limestone locally containing thin intercalated layers/lamination of argillaceous limestone.|
|High-Absorption Limestone||Mainly the mineral calcite. Observed limestone particles are predominately micritic limestone and contain sparse marine fossil remains.|
|Granite, No. 57 Stone||This aggregate granite is mainly composed of quartz and feldspar with lesser but appreciable amounts of biotite locally associated with some muscovite.|
|Green Stone||Meta-basalt that mainly consists of feldspar (perhaps albite), chlorite, and actinolite. Other minerals include calcite, epidote, and biotite were also observed.|
|Granitic Gneiss||Quartz and feldspar with lesser amounts of biotite and muscovite, plus trace amounts of secondary minerals including calcite, epidote, and sericite.|
|Diabase||Diabase/dolorite chiefly consists of plagioclase feldspar and pyroxenes.|
|Quartzite and Sandstone Mix||The quartzite contains quartz and feldspars plus traces of amphibole and mica. The sandstone consists of sand-sized quartz and feldspar clasts. There are also lesser amounts of microcrystalline quartz cemented with what appears to be argillaceous/clayey and carbonate matrix. Traces of calcite and black miscellaneous ferruginous materials were also observed in the matrix of the rock.|
|Marble||Dolomitic marble containing finer-grained portions consisting of darker argillaceous materials. Traces of strained quartz and metachert were observed locally.|
|Dolomite||The aggregate consists of somewhat medium-grained dolomite and what appears to be relatively fine-grained dolomite with a fine-grained argillaceous/clayey matrix. The fine-grained dolomite appears textually similar to argillaceous dolomitic limestone, which is known to have caused ACR and (in recent studies) shown to have caused ASR.|
|Rock Type||Relatively High-Abundance Minerals||Minor Minerals|
|Diabase(dolerite)||Plagioclase feldspars and pyroxenes||Traces of opaque grains
|Rhyolite, dacite, andesite, basalt, trachytic basalt/trachyte, quartzite, and quartz schist||Quartz, sanidine, and plagioclase in rhyolite; plagioclase and quartz in dacite; plagioclase feldspars, pyroxene, and olivine in basalt; Plagioclase feldspars, hornblende, and pyroxene in andesite; alkali feldspar (sanidine) and plagioclase in trachyte/trachytic basalt; Quartz in quartzite and quartz schist||Glass and cryptocrystalline silica in rhyolite, andesite, and dacite; Chlorite after amphibole in dacite; amphibole (hornblende) and Fe oxides (opaque grains) in trachyte and basalt; micas in quartz schist|
|Mainly quartzite with minor sandstone||Quartz||Mica in some quartzite matrix and traces of feldspar|
|Mainly pure limestone; lesser amount of siliceous limestone, argillaceous limestone, and dolomitic limestone||Calcite||Chert, chalcedony, dolomite, argillaceous/clayey laminations, iron sulfide|
Note: the classification of minerals as major and minor is qualitative and based upon only the observed thin sections (two thin sections per sample).
The APL Laboratory is capable of aggregate preparation and sizing; mechanical and durability testing; and characterization and classification of aggregate types for use in concrete, asphalt, and granular base courses and drainage layers. The APL has tools to help troubleshoot performance problems and investigate degradation and distress mechanisms in concrete and other materials used in the transportation infrastructure, working in conjunction with the Chemistry, Concrete, and Asphalt laboratories at TFHRC.
APL resources are used to facilitate research and investigations at TFHRC or in cooperation with Federal and local projects, laboratories, or agencies responsible for the quality and performance of highway materials and structures. Activities include testing, characterizing, and preparing aggregate materials for evaluation in concrete, asphalt, and granular base course mixtures as well as troubleshooting and forensic investigation of performance in highway pavements and other transportation structure applications. Assistance can be provided to FHWA divisions, Federal Lands engineers, and to State DOTs in evaluating special materials or materials performance.
- State-of-the-art transmitted and reflected light compound optical microscope and stereomicroscope
- Rapid-Air 457 Air-Void Analyzer
- State-of-the-art thin section-making equipment
- Mineral aggregate crusher, grinder, and pulverizer
- Sieving and washing equipment
- Full sets of certified standard and intermediate-size sieves for coarse and fine aggregates and for the sizing of minus No. 200 microfine materials using sieves, hydrometer, and laser analysis.
- Various methods of shape, angularity, and texture analysis are available, including:
- Aggregate Image Measurement System (AIMS2) device
- American Association of State Highway and Transportation Officials (AASHTO) Superpave methods
- Durability and compaction equipment include the Micro-Deval device for fine and coarse aggregate degradation in wet exposures, plus standard and modified proctor testing equipment.
- Cutting, lapping, and polishing equipment—for preparation of petrographic thin sections and other specimens—is available in the materials preparation labs.
- The Geotechnical Laboratory at TFHRC also has aggregate triaxial testing equipment available, used for resilient modulus of pavement layers, plus research equipment for characterizing shear strength of compacted granular aggregate materials.