Date of Graduation

7-2020

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering (MSCE)

Degree Level

Graduate

Department

Civil Engineering

Advisor

W. Micah Hale

Committee Member

Cameron D. Murray

Second Committee Member

Gary S. Prinz

Keywords

calcium oxychloride, compressive strength, Deicing chemicals, Low-temperature differential scanning calorimetry, mass change, Thermogravimetric analysis

Abstract

Calcium oxychloride (CAOXY) formation is a serious deterioration mechanism known to cause joint damage in concrete pavements. CAOXY is the product of a chemical reaction between calcium chloride (CaCl2) or magnesium chloride (MgCl) deicing salts and calcium hydroxide in the cementitious matrix. Currently, the accepted CAOXY threshold at which deterioration is mitigated in cementitious paste is 15 g/100 g paste (15 oz/100 oz paste); however, this limit was developed using flexural strength testing. For this investigation, the current threshold was evaluated using compressive strength and mass change over time in paste specimens exposed to CaCl2. Fly ash is used to replace cement (up to a 50% mass replacement) in order to limit CAOXY deterioration. While compressive strength reduction was observed in all specimens despite fly ash replacement level, the results generally validate the current CAOXY threshold level in cementitious paste determined from flexural strength testing.

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