17

OverviewTranscribeVersionsHelp

Here you can see all page revisions and compare the changes have been made in each revision. Left column shows the page title and transcription in the selected revision, right column shows what have been changed. Unchanged text is highlighted in white, deleted text is highlighted in red, and inserted text is highlighted in green color.

2 revisions
Katie Pierce Meyer at Jan 11, 2024 01:30 PM

17

is the most plastic of all materials used in construc-
tion. The experiences of
many
manufacturers of
concrete products have conclusively demonstrated
that the admixeure of hydrated lime
provides work-
ability in the mass and at the same time does not
reduce the consistency to such an extent as to in-
terfere with the rapid manipulation of the material
jii the molds and out of them. As a matter of fact,
it has been found that the labor required to fill and
tamp the molds has been materially reduced, and as
a consequence
the rate of production has been in-
creased. Experience has also demonstrated that
the finished products are more uniform in texture
and color, denser and more impervious, harder and
more durable.
Masonry Mortar.
Lime has been considered one of the basic mate-
rials of civilization ever since it has been known
that a mortar composed of lime and sand would
hold stones and brick in place in buildings, enabling
mankind to provide more comfortable and durable
housing than the primitive skin and wattle huts.
The oldest structural works of man such as
the pyramids, anti many other prehistoric works,
in Vuina, were bu\ilt fame mortar as
the material for binding the individual structural
units together.
This mortar has resisted the
ravages of the ele-
ments throughout the seucceeding centuries, thus
demonstrating the durability of the material. The
monumental structures of continental Europe were
all constructed with lime mortar, giving further
evidence as to the time-resisting value of the mate-
rial, even when subjected to the severe varying
climatic conditions.
No structural material ever used by man has
shown itself sifperior to 'properly prepared lime
mortar made from lump or quick lime, as in encient
and medieval times.
Recent scientific investigations of the subject of
mortars have conclusively demonstrated that even
those composed of portland cement are greatly im-
proved by the presence of lime.
Tests conducted at Columbia University, New
York C
:
ty, have conclusively proved that, a mortar
composed of one part portland cement, one part
limem, and six parts sand (all by volume) produces
brick
masonry which has a compressive resistance
more than a third greater than can be obtained when
only portland cement and sand are used in the vol-
umetric
proportion of 1-3. Other tests conducted
by equally authoritative laboratories have proved al-
so that both cohesion and adhesion are increased by
the use of lime, and that the bedding of masonry, or
in other
words, the area of contact between the
structural unit and the mortar bed, is greatly in-
creased by the use of lime owing to the remarkable
plasticity of lime putty. Another valuable prop-
erty of lime, indicated by the tests at Columbia Uni-
versity, is its remarkable moisture-retaining power.
Owing to this property the “suchtion,” or absorbent
action of structural units, such as brick, exercises
a much less deletriaus effect upon
the mortar, due
to absorbing the water from it.
Lime Plaster.
Soon after man discovered that he could build
better hauses by binding durable units together with
l’me mortar, his sense of refinement and inherent
desire for order and decoration began to be awak-
ened. He became dissatisfied with raugh interiors
and so smeared the rough surfaces of his structures
with some of the mortar. Thus the art of plastering
was born.
The chambers of the pyramids, the ruins of Pom-
peii, and other examples of ancient structures are
plastered. At Pompeii and other ancient ruins lime
plaster in
many
instances has resisted the ravages
of time and the elements better than the surface
of stone or brick to which it was applied. Many
museums and private collections contain specimens
of wonderful frescoes upon great slabs of lime plas-
ter. which is was found possible to remove intact
form the structural surface to which is was original-
il applied.
All of the remarkable examples of Greek, Roman,
Byzantine, Florentine, Medieval, and Renaissance
structures were plastered with lime
plaster, to which
were applied the priceless works of the ancient
artists either by the frescoe or the “laid-in” method.
The remarkable preservation of these art
gems as
regards both color and detail is irrefutable testi-
mony as to the durability and stability of lime plas-
ter.
The interesting buildings of the Elizabethan
period, which were plastered both inside and out-
side with lime plaster, and which have resisted the
climatic conditions found in England during the
intervening centuries, bear futher testimony as
to the lasting quality of lime plaster.
No substitute yet ) devised can compare with
properly prepared lime plaster, as to durability,
stability, cheapness, and sound deadening. Lime
plaster can be worked to
absolutely true surfaces and
angles due to the fact that it remains plastic long
enough to permit perfect working. Lime has a most
remarkable sand-carrying capacity, thus making
for economy. Lime plaster will dry out as rapidly
as any
other material but requires slightly longer
to attain the same degree of hardness. It is perfect-
ly feasible to run three-coat lime
plaster work from
the same scaffold as is done with other materials.
When having a. new home built the
average man
gives no consideration to what is
probably the most
17
TIIL CONCRETE AGE
October, 1920.

17