Show 01 ROAD BUILDING ROCK TESTED value of material gathered in many states 0 iven by department of agriculture prepared by the united states department ot of agriculture results of physical tests in 1010 and 1917 1017 of road building rocks are given in bulletin recently issued by the united states department of agriculture this bulletin supersedes the departments part ments bulletin and supplements bulletin which gave the results of the more common physical tests of approximately road building rocks examined prior to janu 4 1 V ti 4 4 repairing road cheapest and best way Is to attend to holes and ruts while they are small ary 1 1010 the rock tested came from most of the states in a number of cases in addition to other tests the crushing strength of the roe rock k also la Is given the bulletin also contains a complete record of all the crushing strength tests made by the office prior to january 1 1910 1916 the average crushing crashing strength of granites goranites gra and gneiss es lies between and pounds per square inch according to data in the bulletin and the average crushing strength of lime stones and dolomites Is between and pounds per square inch granites goranites Gra gneiss es sandstones and quartzes qu artzes should not in general be used in the wearing course of water bound macadam roads it is stated and and slate should never be used in this manner cementing value tests therefore have been discontinued on these materials |