SPECIFICATIONS FOR NONBITUMINOUS ROAD MATERIALS. 
SPECIFICATION Sqd-1. 
Natural Sand Clay or Topsoil Mixtures for Road Surfacing. 
The sand clay or topsoil shall be composed of a uniform mixture of 
hard durable fragments of sand, together with silt and clay, and may 
advantageously carry a considerable amount of gravel. The mixture 
should be free from an excess of feldspar or mica. 
Cementing value of material under i inch shall be not less than_-_ 35 
The material which will pass a 10-mesh sieve when tested by means of 
laboratory sieves shall meet the following requirement for grading: 
Per cent. 
aha eee eee iva Se Ss 2 ae eee ee Ne 10 to 25 
ESET Be aN a ae ee NA bah ae eel Olea ep eee 10 to 25 
ADYG ES DL SENT LSS SR SE a aie ee 2) Pte Botan ween Ses 50 to 80 
Tests of the cementing value and grading of the sand clay or topsoil 
‘ shall be made in accordance with the following methods: 
Cementing value, U. 8. Department of Agriculture Bulletin 347, p. 19. 
Grading, U. S. Department of Agriculture Bulletin 555, p. 33. 
This specification is intended to cover the quality and approxi- 
mate grading of natural sand clay and topsoil mixtures for use 
particularly in the South Atlantic States. 
The limits of sizes are drawn so as to exclude only sand clay 
and topsoil of manifestly inferior grading. Where heavy traffic is 
to be expected, and likewise in cases where the available mate- 
rial warrants, the minimum allowable percentage of sand should 
be increased and the corresponding maximum allowable per 
centage of both clay and silt decreased. In cases where it is de- 
sired to construct a sand-clay road by admixing sand and clay in 
place, the amounts of each to be incorporated should be so 
gauged that the combined material, after thorough mixing, will 
grade approximately within the limits here shown. 
The maintenance of a sand-clay road should be continuous. 
Patching should be done with material as nearly like that used 
in the original surface as possible.. ; 
General. 
Quality. 
Grading. 
Methods of 
Testing. 
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