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or consumer at such times and under such conditions as would not seriously interfere with routine work. They were, therefore, necessarily incomplete, and lacked the thoroughness desirable. The present investigations will be conducted by a disinterested and wholly impartial party, possessing the requisite time and money, and the results should therefore prove invaluable.

APPENDIX.

LABORATORIES FOR TESTING STRUCTURAL MATERIALS, UNITED STATES GEOLOG

ICAL SURVEY, ST. LOUIS, MO.

CEMENTS, MORTARS AND CONCRETES.

Scope of the Investigations to be Conducted During

the Fiscal Year Ending June 30th, 1906. I. Examination of Constituent Materials.-Sands, gravels, stone, stone screenings, slags, cinders, etc., to be collected by a special representative of the Testing Laboratory sent out for that purpose. A. EXAMINATION OF DEPOSIT

as to the extent and nature of the material from

which the samples are collected.
B. PHYSICAL TESTS IN THE LABORATORY:

1. Mineralogical examination,
2. Specific gravity,
3. Weight per cubic foot,
4. Sifting (granularmetric composition),
5. Percentage of silt and character of same,
6. Percentage of voids,
7. Character of stone as to percentage of ab-

sorption, porosity, permeability, compres-
sive strength and behavior under treat-

ment. C. CHEMICAL ANALYSIS as to the character of the stone, silt, etc., used in these tests.

II. Tests of mortars made with a typical Portland cement and sand, gravel and stone screenings. The typical Portland cement to be prepared by thoroughly mixing a number of brands, each of which must meet the following requirements:

Specific gravity 3.10.

Fineness, residue not more than 8 per cent. on No. 100 and 25 per cent. on No. 200 sieve. Time of setting :

Initial set not less than 30 minutes;

Hard set not less than 1 hour or more than 10 hours. · Tensile strength: 24 hours in moist air..

.175 lbs. 7 days (1 day in moist air, 6 days in water) 500 lbs. 28 days (1 day in moist air, 27 days in water) 600 lbs. One part cement, three parts standard sand:

7 days (1 day in moist air, 6 days in water) 175 lbs. 28 days (1 day in moist air, 27 days in water) 250 lbs. Constancy of volume:

Pats of neat cement three inches in diameter

one-half inch thick at center, tapering to a thin edge, shall be kept in moist air for a

period of 24 hours : A. A pat is kept in air at normal temperature and

observed at intervals for at least 28 days. B. Another pat is kept in water maintained as near

70° F. as practicable and observed at inter

vals for at least 28 days. c. A third pat is exposed in an atmosphere of steam

above boiling water in a loosely closed vessel

for five hours. These pats must remain firm and hard and show no

signs of distortion, checking, cracking or disin

tegration. The cement shall contain not more than 1.75 per

cent anhydrous sulphuric acid or more than 4

per cent magnesium oxide. A test of the neat cement must be made with each

mortar series for comparison of the quality of

the typical Portland cement. A. PHYSICAL TESTS IN LABORATORY: 1. Tensile strength with one part cement to varying

percentages of material under test for 7, 28,

90, 180 and 360 days; 2. Compressive strength with one part cement to

varying percentages of materials under test

for 7, 28, 90, 180 and 360 days; 3. Transverse strength with one part cement to

varying percentages of material under test for

7, 28, 90, 180 and 360 days; 4. Yield in mortar; 5. Tensile strength with cement, material sieved to

one size, 7, 28, 90, 180 and 360 days; 6. Compressive strength with cement, material

sieved to one size, 7, 28, 90, 180 and 360 days; 7. Transverse strength with cement, material

sieved to one size, 7, 28, 90, 180 and 360 days; 8. Porosity;

9. Permeability. III. Tests of concrete made with stone, stone screenings, gravel, sand, cinder, slags, etc.: A. PHYSICAL TESTS IN LABORATORY: 1. Tensile strength with different mixtures as to

proportion and size of the aggregates for 30, 90, 180 and 360 days.

2. Compressive strength with different mixtures

as to proportion and size of the aggregates for

30, 90, 180 and 360 days; 3. Transverse strength with different mixtures as

to proportion and size of aggregates for 30,

90, 180 and 360 days. 4. Absorption. 5. Weight per cubic foot. 6. Modulus of elasticity in compression and tension. 7. Character crushed material used;

(a) Weight per cubic foot,
(6) Size,
(c) Percentage of voids,

(d) Percentage of silt.
8. Porosity;
9. Permeability;
10. Fire resisting qualities;

(a) Effect on hardening concrete,

(6) Effect on hardened concrete. 11. Freezing tests; 12. Yield of concrete; 13. Effect of vibration; (a) On hardening of plain and reinforced

concrete, (6) On hardened plain and reinforced con

crete. 14. Protective influence against corrosion of metal; 15. Adhesion of concrete to metal for varying pe

riods, under varying conditions, up to at least

three years;

(a) Embedded,
(6) On flat surfaces.

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