Please note that this is a scanned copy of a paper originally produced in 1985 and that most of the original was handwritten (of 66 pages, only 10 are typed) so it is not as clear as more recent publications. Please also bear in mind that you may need to do more than just print out the pdf, eg look at some of the tables and graphs online so that you can enlarge parts of them. The effects and performance in concrete of nine commercial water-resisting admixtures has been examined using various test procedures and the detailed results are reported. Three curing procedures and five water penetration test methods were used to assess their performance. All of the admixtures affected workability and air content of the fresh concrete. The compressive strengths were reduced and can be related to air content but not to the effects of water penetration as found by the various test methods. Two admixtures are found to be far superior than the others in terms of reducing water penetration but the difference in dosage rates suggests that one is more economical to use than the other. 66 pages.