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SPECIFICATIONS FOR NONBITUMINOUS ROAD MATERIALS. 13 
SPECIFICATION RC-1. 
Broken Stone and Sand for One-course Portland Cement Concrete 
Pavement. 
BROKEN STONE FOR COARSE AGGREGATE. 
The broken stone Shall consist of fragments of clean durable crushed General. 
rock, free from soft, thin, elongated or laminated pieces, disintegrated 
stone, vegetable, ‘or other deleterious matter. 
The stone shall meet the following requirements: Physical 
RTE COMICS OE Hee Ano NESS Gd a  E  e 8 Properties. 
ROU SATS SSE ee HO eH S Sins eo eae eg ag AMT SN la ee Gg ACN 8 
When tested by means of laboratory screens the broken stone for coarse Grading. 
ageregate shall meet the following requirements: 
Per cent. 
Passinea2-inchyscEeen a not less either ate ee we ee 95 
A MKoyapey IU ovens Sia agen a Lest aCe) ahs CSKOUeVSVen ale, ae Se CaS ENS a OU at a a 40 to 75 
Retained on 44-inch sereen, not less than ___—~___-___ 85 
SAND FOR FINE AGGREGATE. 
The sand shall consist of clean, hard, durable, uncoated stone particles, General. 
preferably siliceous, free from lumps of clay, soft or flakey particles, loam, 
and all organic matter. 
It shall be well graded from coarse to fine, and when tested by means Grading. 
of laboratory screens and sieves shall meet the following requirements : 
Per cent. 
US SLIM Sas he Hy CHES CT CC Tete we el as Sys CA Bate Uae Me 100 
ARO Taye N SHUT agg FDI OV EIS 0 STIS oS hE a Ee 50 to 80 
Total passing 50-mesh sieve, not more than________________ 20 
Passinem OO-mesh sieve not more thaneo se eee 5 
Not more than 8 per cent by weight shall be removed by the elutriation 
test. 
When the sand is mixed with Portland cement in the proportion of 1 Mortar Strength 
part of cement to 3 parts of sand, by weight, according to standard meth- Test. 
ods of making 1:3 mortar briquets, the resulting mortar at the age of 7 
and 28 days shall have a tensile strength of at least 100 per cent of that 
developed in the same time by mortar of the same proportions and con- 
sistency, made of the same cement and Ottawa sand. 
Preliminary acceptance samples shall be subjected to both 7 and 28 day 
tests, and acceptance based thereupon. Samples tested during the progress 
of the work will be accepted on the basis of the 7-day test. 
Tests of the physical properties of the rock, the grading or mechanical Methods of 
analysis of broken stone and sand, and of the mortar tensile strength of Testing. 
sand shall be made in accordance with the following methods: 
1. Toughness: U. S. Department of Agriculture Bulletin 347, page 15. 
2. Grading of Broken Stone: U. S. Department of Agriculture Bulletin 
555, page 32. 
38. Mechanical Analysis of Sand: U. S. Department of Agriculture Bul- 
letin 555, page 33. 
4, Elutriation Test for Sand: U. 8S. Department of Agriculture Bulletin 
555, page 32. 
5. Mortar Tensile Strength Test for Sand: A. S. T. M. Standard Test 
C9-17. 
This specification provides for coarse and fine aggregate to be 
used in the construction of a one-course Portland cement concrete 
pavement. While a coefficient of hardness of not less than 16 for 
the stone for coarse aggregate might well be included under physi- 
cal properties, a requirement for French coefficient of wear has 
been used instead, owing to the fact that few laboratories are 
equipped with a Dorry hardness machine. 
The 15 per cent of coarse aggregate passing the 4-inch screen, 
which is allowed, is permissible only upon the assumption that 
