A comparative study on corrosion behavior of rebar in concrete with fatty acid additive as phase change material. (15th July 2017)

• Record Type: Journal Article
• Authors: Cellat, Kemal; Tezcan, Fatih; Beyhan, Beyza; Kardaş, Gülfeza; Paksoy, Halime
• Is Part Of: Construction & building materials. Volume 143(2017)
• Page Start: 490
• Page End: 500
• Publication Date: 2017-07-15
• Subjects: Phase change materials -- Concrete -- Building materials -- Corrosion -- Fatty acid; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2017.03.165
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Thermally enhanced concrete mixes for energy saving in buildings were developed. Corrosion behavior of rebar embedded in PCM-concrete mixes were studied. Compressive strength of concrete mixes was kept within allowable limits. EIS results shows that corrosion of rebar was not affected by adding PCM. FA and mPCM can be safely used as additive in reinforced concrete mixes. Abstract: The aim of this study is to evaluate thermal and corrosion behavior of concrete with fatty acid (FA) mixture as phase change material (PCM) used for energy saving in buildings. We compared direct use of fatty acid mixture (capric acid and myristic acid) and its microencapsulated form in concrete. The work is based on thermal analyses (DSC, TGA, thermal buffering and thermal regulation effect), and also corrosive behavior of PCM on reinforcement steel (rebar) by using electrochemical impedance spectroscopy. Temperature development of fresh concrete in the first 40 h shows that PCM additives do not affect the hydration reaction, but peak temperature was lowered due to the absorption of heat by PCM. This also indicates retarding effect of PCM in concrete. Additionally, exposed metal surfaces and concrete samples in contact with rebar were examined with SEM for determination of corrosion products. Concrete samples showed enhanced thermal behavior and buffering effect to temperature fluctuations. Compressive strength was decreased by up to 38% with the addition of PCM into concrete. The polarization resistance determined from EIS results does not change significantly addition of PCM in concrete. Thus, PCM has no corrosive effect on metal surfaces in concrete.