Presentation on theme: "Assessment of Type IL Cements for Transportation Applications Ahmad Shalan, Elizabeth Nadelman, Kimberly E. Kurtis, Lawrence F. Kahn School of Civil and."— Presentation transcript:
Assessment of Type IL Cements for Transportation Applications Ahmad Shalan, Elizabeth Nadelman, Kimberly E. Kurtis, Lawrence F. Kahn School of Civil and Environmental Engineering, Georgia Institute of Technology Introduction Future Work This work is supported by the Georgia Department of Transportation under project number GDOT 02-127. Both AASHTO and ASTM have recently approved significant changes to their specification for cements or blended cements, allowing an increase in the allowable mass of ground limestone (CaCO 3 ) in some portland cement to approximately 15% by mass, creating what are known as “limestone blended cements”, or “Type IL cements.” This research will compare regionally produced limestone blended cements with conventional portland cements in terms of composition and fineness, evaluate the influence of increasing ground limestone addition rates through the assessment of key material properties, examine the relative sensitivity of those properties to field conditions, and assess the combinations of limestone blended cements with fly ash and slag. Compare material and early age properties of regionally produced Type IL limestone cements to those of Type I ordinary portland cements with similar chemical compositions. Evaluate the performance of Type IL concretes conforming to GDOT specifications for Class A, AA and AAA concrete. Materials Characterization and Testing Research Program Technical Literature Review Materials Characterization and Testing Development of Concrete Mixes Assessment of Mechanical Properties Assessment of Durability finer coarser Additional Tests: Autogenous Shrinkage (ASTM C1698), Chemical Shrinkage (ASTM C1608) Task 1Task 2Task 3Task 4Task 5 Cement Composition and Fineness: QXRD and Laser Particle Size Analysis Vicat Setting Time (w/c = 0.29): ASTM C191 Paste Flow (w/c = 0.29): ASTM C1437 Isothermal Calorimetry (w/c = 0.445): ASTM C1679 Acknowledgements Assessment of Concrete Properties and Durability Compressive Strength (w/cm = 0.445): ASTM C39 Drying Shrinkage (w/cm = 0.445): ASTM C157 Early-Age Properties: Hydration: Rapid Chloride Permeability Test (w/cm = 0.445): ASTM C1202 Additional Tests: Freeze/Thaw Resistance (ASTM C666) Surface Resistivity Test (w/cm = 0.445 and 0.40): AASHTO TP95 Additional Tests: Elastic Modulus (ASTM C469), Tensile Strength (ASTM C496) Mechanical Properties and Dimensional Stability: Durability: Increased rate of reaction Decreased rate of reaction Onset of fly ash reaction (LS) Onset of fly ash reaction (PC) High Moderate Low Very Low Permeability Low Moderate High Permeability Low Moderate High Permeability PhasePCABCDE C 3 S (%)53.449.659.447.854.959.4 C 2 S (%)22.819.09.522.715.215.3 C 3 A (%)3.03.32.91.96.73.6 C 4 AF (%)11.19.312.612.78.511.7 Limestone (%)2.716.011.612.610.26.2 Five Type IL cements (A-E) and one portland cement (PC) were initially examined. Examine the sensitivity of Type IL concrete properties to variations in mixing temperature and curing conditions. Assess the performance of concretes containing various dosages of supplementary cementitious materials such as fly ash and slag.