Development of Reduced Cementitious Materials Concrete (RCMC) Mixtures for Bridge Decks and Rails

Authors

Soumitra Das, University of Nebraska-LincolnFollow

First Advisor

Dr. George Morcous

Date of this Version

Summer 7-2023

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Construction Engineering and Management, Under the Supervision of Professor George Morcous. Lincoln, Nebraska: August, 2023

Copyright © 2023 Soumitra Das

Abstract

Right after construction, drying shrinkage of restrained concrete bridge decks and rails causes early-age cracking that eventually leads to delamination and spalling of concrete due to insertion of water and chemicals, and corrosion of reinforcing steel. The main objective of this research is to control early-age shrinkage cracking by reducing cementitious material content in the 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 (known by 47BD). 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), and durability properties (freeze and thaw resistance, chloride resistivity, drying shrinkage, 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 that reduces production cost and carbon footprint.

Advisor: George Morcous