Influence of Chloride in Mortar Made of Portland Cement Types II, III, and V on the Near-Field Microwave Reflection Properties

Abstract

Corrosion of steel rebar in reinforced concrete structures, can be induced by the presence of chloride in the structure. Corrosion of steel rebar is a problematic issue in the construction industry as it compromises the strength and integrity of the structure. Although techniques exist for chloride detection and its migration into a structure, they are destructive, time consuming and cannot be used for the interrogation of large surfaces. In this investigation three different portland cement types; namely, ASTM types II, III and V were used, and six cubic (8' X 8' X 8') mortar specimens were produced all with water-to-cement (w/c) ratio of 0.6 and sand-to-cement (s/c) ratio of 1.5. Tap water was used when producing three of these specimens (one of each cement type). For the other three specimens calcium chloride was added to the mixing tap water resulting in a salinity of 2.5%. These specimens were placed in a hydration room for one day and thereafter left it the room temperature with low humidity. The reflection properties of these specimens, using an open-ended rectangular waveguide probe, were monitored daily at 3 GHz (S-band) and 10 GHz (X-band). The results show the influence of cement type on the reflection coefficient as well as the influence of chloride on the curing process and setting time.

Meeting Name

Subsurface Sensing Technologies and Applications II (2000: Jul. 30-Aug. 4, San Diego, CA)

Department(s)

Electrical and Computer Engineering

Keywords and Phrases

Chloride Detection; Chloride Penetration; Corrosion Of Steel; Microwave Reflection Properties; Near-Field; Problematic Issues; Reflection Properties; Room Temperature; Concretes; Construction Industry; Microwaves; Mortar; Nondestructive Examination; Portland Cement; Reinforced Concrete; Steel Corrosion; Chlorine Compounds; Composition Effects; Concrete Construction; Curing; Electromagnetic Wave Reflection; Hydration; Microwave Measurement; Salinity Measurement; Setting; Image Sensors; Near Field Microwave Techniques; Reinforced Concrete Structures; Steel Rebar Corrosion; Concrete; III And V; Near-Field Techniques; Nondestructive Testing; Portland Cement Type II

International Standard Serial Number (ISSN)

0277-786X

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2000 SPIE--The International Society for Optical Engineering, All rights reserved.

Publication Date

01 Aug 2000

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