School of Civil and Environmental Engineering

Ph.D. Thesis Defense Announcement

MULTISCALE INVESTIGATION OF NOVEL ALTERNATIVE CEMENTITIOUS MATERIAL SYSTEMS

By

Prasanth Alapati

Advisor:

Dr. Kimberly E. Kurtis (CEE)

Committee Members:

Dr. Lawrence F. Kahn (CEE), Dr. T. Russell Gentry (CEE), Dr. Preet Singh (MSE), Dr. Maria Juenger (CAEE at UT Austin)

Date & Time: Friday, October 25th, at 11:00 am

Location: Sustainable Education Building (SEB), Room 122

The necessity and the universality of concrete infrastructure prompt innovation in addressing the global challenge of meeting societal needs in the most sustainable and economical ways possible. Increasing the use of non-portland cements or "alternative cementitious materials" (ACMs) is of growing interest due to their unique properties and to their potential to reduce the environmental footprint of concrete.  The unique properties of ACMs may vary by material, but include rapid setting, rapid strength development, higher ultimate strength, improved dimensional stability, and increased durability in aggressive environments. The increased strength and increased durability further contribute to enhanced service life, which can help offset initially higher materials costs, and also to enhanced sustainability.
In the past, most ACMs were primarily used in limited specialty applications, and some of them have been shown in lab-scale studies to be feasible for the partial or full replacement of traditional portland cements used in concrete. However, there is a limited understanding of the scalability of construction with these material systems, their long-term performance, and durability in a range of environments, and their structural response when subjected to transportation-relevant loading conditions. This thesis presents the results from the comprehensive investigation of the applications of these commercially available ACMs in durable and sustainable transportation infrastructure, which include the early-age and long-term material properties as well as multi-scale durability investigations. 
A novel multi scale approach was proposed to design concrete mixtures with these commercial ACMs to meet both the prescriptive requirements and the performance targets. The multi approach involves (i) using multiple advanced material characterization techniques to understand how these commercially blends hydrate, (ii) changing their fresh properties to meet the prescriptive requirements without adversely affecting their long-term material properties to meet the performance targets. New test methods and protocols also involving multi scale material characterization were proposed to gauge the long-term performance of these ACMs against wide range of exposure conditions. These new test methods were designed relying as much as possible on existing test methods for traditional portland systems, to facilitate rapid adoption of the ACM formulations. From this, guidance for the lab scale investigation, and, guidance for the ACM selection and mixture design for use in transportation infrastructure, primarily in the aspects investigated in this thesis are provided.