Nebraska LTAP
Date of this Version
12-8-2023
Document Type
Article
Citation
Das, S., Marcus, G., and Hu, J. (2023). Low-Cement Concrete Mixture for Bridge Decks and Rails. NDOT Research Report SPR-FY22(001).
Abstract
Right after construction, drying shrinkage of restrained concrete bridge decks and rails causes early-age cracking, insertion of water and chemicals, and corrosion of reinforcing steel that eventually leads to delamination and spalling of concrete. The main objective of this research is to control early-age shrinkage cracking by reducing cementitious material content in bridge deck and rail concrete mixtures. Several reduced cementitious materials concrete (RCMC) mixtures were developed by optimizing aggregate particle packing and conducting overall performance evaluation. This evaluation was carried out in three phases. The first phase investigated the feasibility of new RCMC mixtures by testing workability, compressive strength, and chloride penetrability when cementitious materials content is reduced by 50, 100, and 150 lbs per cubic yard compared to the standard bridge deck concrete mixture of Nebraska. The second phase investigated fresh properties (slump and air content), early-stage properties (setting time and heat of hydration), mechanical properties (compressive strength, modulus of rupture, modulus of elasticity, shear strength, slant shear strength, and bond strength), durability properties (freeze and thaw resistance, and chloride resistivity), and shrinkage properties (free and restrained shrinkage). The third phase investigated the batching, mixing, handling, pumpability, and finishing of the RCMC mixtures by casting mockup deck panels using ready mixed concrete. All the developed RCMC mixtures have demonstrated a comparable performance to the standard mixture while having a reduced cementitious materials content, which is expected to reduce production cost and carbon footprint due to the lower cement content.