METHODS OF SAMPLING AXD TESTING HIGHWAY MATERIALS 35 
strength. When the height is more than twice the diameter : that is. when the 
ratio is greater than two, no correction need be made. For other ratios cor- 
rections shall be made as indicated in the following table. Values not given in 
the table shall be determined by interpolation : 
Ratio of height of cylinder to diameter (-j\ 
1.75, multiply crushing strength by 0.98 
1.50, multiply crushing strength by . 95 
1.25, multiply crushing strength by .94 
1.10. multiply crushing strength by . 9U 
1.00, multiply crushing strength by 2 
0.75, multiply crushing strength by . 7m 
0.50, multiply crushing strength by . 50 
8. The direction of the application of the load in the compression test shall be 
stated with reference to the direction of the compaction of the mass of con- 
crete in the structure, and where it is practicable the compression load shall be 
applied in the same direction. In order that the tests be made under uniform 
conditions as to moisture content, the test specimens shall be completely sub- 
merged in water for 4fe hours and the compression test shall be made immedi- 
ately thereafter. 
25. METHOD OF TEST FOR ABSORPTION OF CONCRETE 
1. Specimens for the absorption test shall be apparently sound, solid pieces of 
concrete and shall not show cracks or fissures. The specimens shall be so 
marked as to permit the identity of each one to be ascertained at any stage of 
the test. 
2. Preparatory to the absorption test all specimens shall first be weighed and 
then dried in a drier or oven at a temperature of not less than 110' C. 
(230"- F.) for not less than three hour-. After removal from the drier, the 
specimens shall be allowed to cool to a temperature of 20' to 25° C. i68° to 
77" F.) and reweighed. If the specimens were apparently dry when taken, 
and the second weight eloseiy checks the first, the specimens shall be considered 
dry. If the specimens were known to be wet when taken, they shall be placed 
in the drier for a further drying treatment of two hours and reweighed. If the 
third weight checks the second the specimens shall be considered dry. In 
case of any doubt the specimens must be redried for two-hour periods until 
checks weights are obtained. 
3. The balance used shall be sensitive to 0.05 gram when loaded with 1 kilo- 
gram and weighings shall be read at least to the nearest grain. When other 
than metric weights are used the same order of accuracy must be obtained. In 
reweighing after immersion the specimens shall be removed from the water, 
not allowed to drain more than one minute, the superficial water removed by 
towel or blotting paper, and the specimens at once put upon the balance. 
4. Specimens after weighing shall be placed in a suitable receptacle, covered 
with distilled water or rain water, raised to the boiling point and boiled, for 
five hours, and then cooled in water to a final temperature of 10° to 15* C. 
(50° to 59' F.). 
5. The test results shall be calculated as percentages of the initial dry weight 
carried to the nearest first decimal place. The results shall be reported sepa- 
rately for each individual specimen, together with the mean of the specimeuc 
comprising the sample. 
26. METHOD OF TEST FOR QUALITY OF WATER TO BE 
USED IN CONCRETE 
1. Acidity and alkalinity. — The acidity or alkalinity shall be determined 
with standard solutions of one-tenth normal alkali or acid, respectively, using 
not less than 2oO cubic centimeters of the water under examination. Phenol- 
phthalein or methyl orange should be used as an indicator. Excessive acidity 
or alkalinity indicates the necessity for further tests. 
2. Total solids and inorganic matter. — Five hundred cubic centimeters oi 
the water shall be evaporated to dryness in a weighed dish. For this purpose 
a platinum dish of 100 to 200 cubic centimeters capacity is found most con- 
venient. The dish shall be nearly filled with the water and placed on a water 
bath, additional portions of the sample of water being added from time to time 
until 500 cubic centimeters have been used. The contents of the dish shall be 
