This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ...but it is deficient in filler and, in consequence, does not carry enough bitumen. Of the components entering into the mixture but 8.2 per cent. was dust, and it is probable that this was a coarse material, and at least half as much again should have been used. With a sufficient amount of filler the asphalt cement would ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ...but it is deficient in filler and, in consequence, does not carry enough bitumen. Of the components entering into the mixture but 8.2 per cent. was dust, and it is probable that this was a coarse material, and at least half as much again should have been used. With a sufficient amount of filler the asphalt cement would be of suitable consistency for use in the cold climate where this pavement was laid, but with the absence of sufficient filler it would seem to be too soft. In a small southern city, in the same year, a surface mixture was laid, of which the extremes and average composition as regards percentage of bitumen were as follows: There is a great lack of uniformity in this mixture, both in percentage of bitumen and in its consistency, the variations being far greater than should occur in good practice. The amount of dust was only 60 lb. with n cu. ft. of sand, which shows that there must have been a deficiency in filler, although the amount of material passing a 200-mesh sieve appears to be sufficient. The sand grading shows a lack of particles of sizes passing the 80-and 100-mesh sieves and a large amount of coarse sand, but in a small city this is not a serious consideration if the mixture is satisfactory in other respects. In another northern city a mixture was laid which shows similar wide variations. PASSING MESH Penetration, 133-50. It will be seen that the sand grading in this town was not carefully regulated. It was at times good, as in the case of the mixture carrying 11 per cent. of bitumen, and at times very bad, as in the case of the mixture carrying 8.2 per cent. of bitumen. The percentage of filler was very deficient at times, which, with the sand grading accounts in part for the low bitumen, and at other times approaches a more satisf...
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