00969928

Monograph

http://onlinepubs.trb.org...y/NCHRP85_Final_Report.pdf

This Innovations Deserving Exploratory Analysis (IDEA) project tested the concept of permanently waterproofing concrete by incorporating a waterborne dispersion of soybean oil phosphate ester polyol (SOPEP) into the concrete at the time of mixing. Rebar corrosion caused by water and chloride permeation through capillaries in concrete leads to loss of reinforcement of the concrete, which leads to highway surface deterioration and potholes. Various additives have been used to waterproof concrete, but "leakage" of the oils and mobile organics from the concrete has been a problem. It was postulated that the water dispersible ionomeric soybean oil phosphate ester would initially act as a plasticizer/air entrainment admix. Then as the cement hydrated, SOPEP would be concentrated in the capillaries and the phosphate portion of the oil would adhere to the concrete matrix of the capillary walls and "lock" the oil in the cement capillaries to give permanent waterproofing so that oil would not leach out to the surface causing traction problems. The oil bound in the concrete capillaries would minimize trapped water and not only minimize freeze-thaw damage, but also slow the permeation of water and chloride into the concrete and give longer concrete highway service life. The idea of waterproofing the concrete from within the concrete capillaries should be possible, without affecting the skid resistance of the surface. The scope of this project was to test the hypothesis and evaluate reduced water permeation in treated concrete. In concrete tests, SOPEP did increase fresh concrete slump as expected, but it was not as effective as commercial superplasticizers. It also retarded cure as expected for a phosphate. SOPEP did adhere strongly to the concrete matrix. Unfortunately, it bonded so strongly and so soon, that it did not accumulate in the capillaries as much as expected. At 5% by weight of the cement, SOPEP reduced water absorption by only about 15%. Compressive strength of the concrete at 18 days cure was reduced greater than the 10% reduction considered acceptable. SOPEP was also sprayed on fresh concrete and evaluated as a possible curing agent to retard drying of concrete--it was marginally effective.

This NCHRP-IDEA investigation was conducted by Texas State University, San Marcos and the University of Texas, Austin. 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

NCHRP-IDEA Project 85

NCHRP-IDEA 85

English

19 p.

2004-2

NCHRP-IDEA Program Project Final Report

Figures (7) ; References (7) ; Tables (7)

Compressive strength; Concrete curing; Concrete pavements; Performance; Soybeans; Technological innovations; Water reducing agents; Waterproofing

Innovations Deserving Exploratory Analysis (IDEA) (Program)

Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces

TRIS, TRB

Feb 23 2004 12:00AM