Research projects by Dr. Goulias
High Performance Concrete Pavements
Sponsors: MSHA, FHWA, Concrete Industry
The objective of the study was to examine the benefits of using innovative pavement concrete mixtures for enhancing the flexural fatigue resistance and improving the shrinkage behavior of concrete pavement mixtures. The study was sponsored by Federal Highway Administration (FHWA) under "Test and Evaluation Project 30" (TE-30), "High Performance Concrete Pavement" (HPCP) and by the Maryland State Highway Authority (MSHA). In addition, the concrete industry is actively involved in this significant and innovative effort.
The study included extensive laboratory evaluation of several experimental fiber reinforced concrete and low shrinkage mixtures. Selected concrete mixtures from the laboratory study were used in the construction of test sections in the Salisbury bypass on US-50 for evaluating their performance under in-service loading and environmental conditions. Pavement instrumentation was also installed and includes: concrete strain gages for measuring slab surface stains under traffic loadings; linear variable displacement transducers (LVDTs) to measure concrete slab deflections under traffic; thermocouples to measure concrete slab temperature profile; vibrating wire gages to measure long term strains in the concrete slabs; and Whitmore plugs to measure changes in joint width. The constructed instrumented experimental pavement sections are currently undergoing load testing. Profile measurements of diurnal (temperature curling) and seasonal (moisture warping) slab changes are also included as part of the field monitoring program. The analytical portion of the study included finite element analysis (FEM) for both pre-construction predictions of expected pavement response and post construction monitoring of the experimental concrete slabs. Particular emphasis is placed on comparisons of stiffness degradation rates between the fatigue test section and the control section and on differences in temperature curling and moisture warping between the shrinkage test section and the control section.
Field Instrumentation at US-50
Paving US-50 with experimental Fiber Reinforced Concrete
New technology Based Approach to Advance Higher Volume Fly Ash Concrete with Acceptable Performance
Sponsors: Department of Energy – CBRC, Concrete Industry
This research project is undertaken with the National Ready Mix Concrete Association (NRMCA) and concrete experts in maturity. It suggests novel science-based approaches to address the slower rate of strength gain and delayed setting times of HVFA concrete. This project will address the two major stumbling blocks, lower early-age strengths (less than 7 days) and delayed initial setting times, which prevent the large scale utilization of HVFA concrete. Objectives of the project are: to demonstrate by using a maturity based approach that HVFA concrete in the structure has sufficient early-age strengths to allow for optimized construction scheduling; and to demonstrate that by using some suitable chemical admixtures or additions the initial setting times of Class C fly ash concrete is not delayed. Based on these approaches a step by step procedure will be developed that the concrete producer and the construction team can adopt to manage the resulting properties of HVFA concrete during mixture development and construction scheduling. The project includes extensive filed and laboratory testing with instrumentation related to the maturity concept of concrete, and non destructive testing of concrete using the pull out method.
Preparation of Instrumented Concrete Blocks with pullout inserts and I-buttons for Maturity testing
Sure Cure System and Concrete Cylinders
Evaluation of Aggregate for Masonry Mortar: Aggregate Characteristics and Impact on Mortar Properties
Sponsors: National Staone National Stone, Sand & Gravel Association, NSSGA, Portland Cement Association, PCA, and aggregate industry
ASTM C 144, Standard Specification for Aggregate for Masonry Mortar, contains grading requirements for natural and manufactured sands. C 144 is the sand required to produce mortar using the common specification in North America, ASTM C 270, Mortars for Masonry. Mortar made with sand meeting the gradation requirements of C 144 requires no physical property testing. A provision in C 144 allows sand not meeting the gradation to be used, provided mortar is tested to ensure compliance with specific physical properties. This testing adds cost and time to the process of establishing mortar proportions.
Increasingly, quarries have difficulty supplying natural and manufactured sands to meet C 144 gradation specifications. This project would look at sand gradation and its effect on the physical properties of mortar, such as compressive strength, air content, flow, and water retention. It is envisioned that the results of this study will impact the profession since it would be the basis for balloting a revision or modification of ASTM 144 by modifying the gradation requirements.
Aggregate and Mortar Testing
Fine Aggregates sources included in the study
