00464513

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http://onlinepubs.trb.org...trr/1987/1110/1110-003.pdf

https://scholar.google.co...erke&publication_year=1987

Research on the topic of calcium sulfate impurities in deicing salts adversely affecting the durability of portland cement mortar is covered in this paper. Natural rock salt may contain as much as 4.0 percent calcium sulfate. When combined with chloride solutions the solubility of calcium sulfate increases by as much as 3.5 times; hence, the calcium sulfate impurities contained in rock salt brine become highly detrimental, causing attack on cement mortar samples. These impurities can collect in pavement joints and cracks, reaching high concentrations through evaporation and the repeated use of deicing salts. Such a destructive mechanism may account for premature field failure of pavements that passed durability tests in the laboratory. Durability studies using brines containing differing amounts of gypsum in proportion to the sulfates occurring in natural rock salts have been conducted. To model field conditions, samples were concurrently subjected to brines and rapid freeze-thaw testing. Deterioration proved so rapid that testing was stopped at 88 cycles. Tensile tests showed strength losses up to 40 percent for samples subjected to brine solutions containing gypsum impurities. Mercury intrusion porosimetry showed significant losses in pore volume for the treated samples as compared to samples frozen and thawed in water only. X-ray diffraction tests discovered increased amounts of ettringite and Friedel's salt, a tricalcium aluminate chloride hydrate.

Publication of this paper sponsored by Committee on Performance of Concrete. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

01492602

pp 16-23

1987

Transportation Research Record

66th Annual Meeting of the Transportation Board

030904460X

Print

Figures (9) ; References (14) ; Tables (4)

Calcium sulfates; Concrete; Deicing chemicals; Deterioration; Diffraction; Durability; Ettringite; Freeze thaw tests; Gypsum; Halite; Mercury; Pore space; Porosimeters; Portland cement concrete; Solubility; Sulfates; Tension tests; X rays

Friedel's salt; Mercury porosimetry; X-ray diffraction

Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I32: Concrete

TRIS, TRB

Dec 31 1987 12:00AM

• A NEW PROCESS FOR THE LAYING OF MONOLITHIC COMPOSITE CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS
• COMPARISON OF CONCRETE PAVEMENT REHABILITATION TECHNIQUES IN OHIO DEMONSTRATION PROGRAM
• CONSTRUCTION OF A THIN-BONDED PORTLAND CEMENT CONCRETE OVERLAY IN SOUTH DAKOTA
• DRAINCRETE IN PAVEMENT REHABILITATION
• EARLY AGE PROPERTIES OF MAGNESIUM PHOSPHATE-BASED CEMENTS UNDER VARIOUS TEMPERATURE CONDITIONS
• EARLY STRENGTH OF CONCRETE PATCHING MATERIALS AT LOW TEMPERATURES
• FIELD EVALUATION OF CONCRETE PAVEMENT CONSOLIDATION
• FIELD EVALUATION OF DOWEL PLACEMENT IN CONCRETE PAVEMENTS
• FIELD PERFORMANCE OF BONDED CONCRETE OVERLAYS
• MOISTURE RETENTION TESTS AND AGITATION FOR MEMBRANE-FORMING CURING COMPOUNDS FOR PORTLAND CEMENT CONCRETE
• MONTANA'S EXPERIENCE WITH AND STRATEGIES FOR CONCRETE PAVEMENT REHABILITATION
• PERFORMANCE OF STEEL FIBER REINFORCED CONCRETE USING LARGE AGGREGATE
• PETROLOGICAL STUDIES ON CARBONATE AGGREGATE RESPONSIBLE FOR PAVEMENT D-CRACKING IN SOUTHERN MANITOBA, CANADA
• THE RELATIONSHIP OF FERROAN DOLOMITE AGGREGATE TO RAPID CONCRETE DETERIORATION