Masonry Magazine June 1963 Page. 15
Maracteristics of Limestone
Indiana limestone stone formed of shell fragments and is practically non-crystalline in character. Characteristically a free-stone without a cleavage plane, it possesses a reliable uniformity of composition and structure. It has high inelasticity and adapts to extreme temperature changes without damage and meets other prerequisites of permanence demanded of modern building materials.
Limestone is 'graded' according to the fineness of the grain of the stone. Five grades are available. All are available in degrees of "buff" and "gray" color. Both color and texture uniformity are important in the "select" (top) and 'standard' (second from top) grade of Indiana stone, even though standard is larger-grained than select. "Variegated" (next to standard) is unselected in color and texture and is the most economical grade of Indiana stone. "Rustic" (bottom) is found in a range of granular formations, present in this grade of Indiana Limestone. "Old grade" (not illustrated) is coarse-grained variegated.
Color
Indiana limestone is marketed in two color-tones: varying shades of buff (from a light creamy buff or buff-gray to a distinct brownish-buff) and gray (silvery gray with a slight bluish cast) and an irregular mixture of the two called variegated.
Fire Resistance
Indiana limestone is fire resistant. It calcines above 1,500°F and will not spall, crumble, split or check when drenched with cold water.
Weight
The average weight of dry (seasoned) Indiana limestone is 144 pounds per cubic foot.
Strength-recommended Values
This data is taken from information developed by tests made at the Bureau of Standards, Washington, D. C. on representative samples of seasoned stone.
a. Crushing strength: Crushing strength varies from about 5,000 to 7,000 lbs./sq. in. (average close to 5,500 lbs./sq. in.)
b. Tensile strength. Tensile strength varies from 300 to 715 lbs./sq. in. (average 535 lbs./sq. in.). Using a safety factor of ten (10) with this average results in a conservative working value of 50 lbs./sq. in.
c. Transverse strength. The modulus of rupture varies from about 900 to 1,600 lbs./sq. in. (average approximately 1,250 lbs./sq. in.) A safety factor of ten (10) makes a working stress of 125 lbs./sq. in. applicable to the design of lintels and similar "stone beams."
d. Shear. Tests were made in three directions. Shear developed ran from 900 to 2,300 lbs./sq. in. (average 1,600 lbs./sq. in.)
Finishes
Indiana Limestone is produced in various grades and colors as well as surface finishes. They are: Sand Sawed, Chat Sawed, Shot Sawed, Splitstone, Brushed, Rubbed, Machine, Tooled, Plucked, Nicked Bit and Shot Sawed Variations. The machine finish is also known as "smooth" and it is the most popular and economical for the majority of work. The machine finish is produced by machines called planers without hand work other than the removal of objectionable tool marks where they occur.
e. Elasticity. Coefficient of elasticity has been established at 4,400,000 Ibs./sq. in.
f. Expansion. Coefficient of expansion has been established as 0000027 inch per degree Fahrenheit.
Proof of high standard of craftsmanship in Indiana limestone is revealed in this picture, showing Henry Morris, Ellettsville, Ind. working on one of the two large figures of Christ which were completed for a Newton, Massachusetts church. Because of its homogeneous nature, Indiana limestone is well adapted to sculpture, impossible in other materials.
SUCCESSFUL MASONS USE BIG CHIEF MIXERS
for
RE BATCHES
MOOTHER
MIXES
Sizes
From
3-½ to
9 cu. ft.
MODERN
SCAFFOLDING
METHODS
for the
MASON CONTRACTOR
PSS
THE PATENT SCAFFOLDING CO., Inc.
38-21-12th St. Long Island City 1, N. Y.
Branches in all Principal Cities
15
WRITE:
N. 62nd St.,
BIG CHIEF DIVISION
Douglas Motors Corp.
Milwaukee, Wisconsin,
Dept. MCN-363 BC
ONRY
June, 1963