Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Howard, Isaac L.

Committee Member

Freyne, Seamus F.

Committee Member

Moser, Robert

Committee Member

Stone, Tonya W.

Committee Member

Vahedifard, Farshid

Other Advisors or Committee Members

Keith, Jason M.

Date of Degree

8-9-2019

Document Type

Dissertation - Open Access

Major

Civil Engineering

Degree Name

Doctor of Philosophy

College

James Worth Bagley College of Engineering

Department

Department of Civil and Environmental Engineering

Abstract

This dissertation covers concrete and cement paste (CP) containing portland-limetsone cement (PLC) for the purpose of understanding mainly mechanical property behaviors. PLC has been consistently investigated by researchers over the past decade who have found equal and often superior performance with PLC, but few researchers have found reasons why. Throughout this dissertation CP cylinders are used to help understand concrete. By understanding the CP (cementitious materials, water, admix, and no fine or coarse aggregates) portion of concrete, it is believed further understanding can be achieved. The interaction of CP and aggregates, or paste aggregate bond (PAB), is exceptionally important. Literature review suggests PAB can be affected by chemical and physical properties of aggregates as well as cement which dictates the mechanical property performance of concrete. CP measurements used herein are mainly compressive strength, however there were other measurements, such as thermal setting, collected as well. CP properties whether thermal or mechanical, generally agreed with concrete results. Additionally, CP compressive strengths were found to have value beyond what was previously known. Mainly that CP compressive strengths can help diagnose concrete behavior. CP used with concrete measurements can give some indication, not previously available, concerning PAB and bonding efficiency. However, the CP measurements had high variability. As such, a new CP production method was developed alongside different analysis techniques to reduce the variability. CP was further used with concrete to recommend a factor for balancing fineness and limestone percentage in PLC. Next, CP measurements were used with 74 concrete mixtures for investigating the Mississippi Department of Transportation fly ash replacement level limits for ordinary portland cement (OPC) and PLC for implementation into the Mississippi market. Lastly, this dissertation delved into non-production concrete mixtures with few ingredients (washed aggregates, cementitious materials, and water) to discover mechanisms behind PLC and OPC behaviors. From CP and concrete measurement perspectives, it is recommended that PLC in the MS marketplace be implemented without hesitation. From the conclusions herein, there does not appear to be many cases where OPC considerably outperforms PLC. In almost every case, PLC performs equivalent or better than OPC when numerous properties are considered.

URI

https://hdl.handle.net/11668/14555

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