The Fall 2020 newsletter of the National Concrete Consortium has the following items:
• Moving Advancements into Practice (MAP) Brief titled Overview of Cement-Stabilized Subgrade Soils is now available from the NC² Resource Library. This Fall 2020 MAP brief summarizes Gross and Adaska's recently published Guide to Cement-Stabilized Subgrade Soils that is an outcome of CP Tech Center collaboration with the Portland Cement Association.
• FHWA Concrete Clips: Blended Cements and Supplementary Cementitious Materials
• Effects of Concrete Age on Coefficient of Thermal Expansion of Paving Mixes and Its Significance in Unbonded Overlay Design: With the advancement in rigid pavement design and advent of AASHTOWare Pavement Mechanistic-Empirical (ME) Design (American Association of State Highway and Transportation Officials, Washington, DC) as the latest design tool, increasing emphasis is being placed on the coefficient of thermal expansion (CTE) of concrete. The CTE affects the performance of rigid pavements in a significant manner, with a higher CTE corresponding to greater curling and resulting in greater pavement distresses. Prior research has had conflicting views regarding CTE variation with age and there has been very little to no research on the effects of the CTE on the performance of unbonded concrete overlays (UBCOs). This study was performed to investigate the variation in CTE with concrete age through laboratory testing and to further quantify the effects of CTE variation on UBCO design.
• Strategies for Concrete Pavement Preservation (Interim Report): The use of the term “preservation” for concrete pavements is somewhat of a misnomer in that many preservation treatments are actually stop-gap measures used to address visible signs of deterioration in the existing pavement. The treatments address the symptoms of the problem but may not directly address the underlying causes of the distress, which can progress until requiring even more significant rehabilitation, or perhaps even reconstruction. This report redefines the term concrete pavement preservation as “preserving the existing concrete pavement structure to extend its service life for as long as possible by arresting, greatly diminishing or avoiding the pavement deterioration process.” his report reviews the primary factors affecting concrete pavement performance and strategies for concrete pavement preservation. A state-of-the-practice review on the approaches for evaluating the condition of concrete pavements that will help in developing long-term concrete pavement preservation strategies and the engineering economic analysis techniques that can be employed to evaluate the cost-effectiveness of various preservation strategies is also included.
• Nondestructive Corrosion Evaluation of Reinforced Concrete Bridge Decks with Overlays: An Experimental Study: Concrete corrosion induced by deicing agents can decrease the durability of concrete bridge decks by causing cross-sectional loss of reinforcement, concrete delamination and spalling owing to the expansion of corroded reinforcement. The installation of overlays can extend the service life of the deteriorated decks. However, overlays present challenges in the evaluation of the corrosion condition of the underlying decks. This laboratory study employed three nondestructive testing (NDT) methods to assess the effects of seven types of overlays on corrosion evaluation for concrete bridge decks.
• Field Implementation of Compacted Concrete Pavement: The main objective of this research was to investigate the performance of Compacted Concrete Pavement (CCP) with special surface texture design features that can reduce construction cost and secure safe and durable surface texture. This research was part of a larger project undertaken by the City of Mexico, MO, in collaboration with the Missouri Department of Transportation (MoDOT). The CCP mixture was evaluated for key fresh properties (unit weight, air content and Vebe consistency), mechanical properties (compressive strength, flexural strength and modulus of elasticity), drying shrinkage and durability (air-void system, freeze-thaw resistance, scaling resistance, and bulk and surface resistivity).
Click here to links to each of the above reports and the entire newsletter.
National Ready Mixed Concrete Association