Avant-garde solutions

Added: (Fri Nov 04 2005)

Pressbox (Press Release) - OBTAINING CONSTRUCTION MATERIALS BASED ON LUNAR SOIL WITH THE USE OF
REGULARITIES OF A ALKALINE BINDING SYSTEMS.

The assimilation of deep space is connected to the development of new
process engineering's of obtaining of binding materials and building
aggregates on their basis.
The purpose of the present paper is to explore the possibility of using
lunar soil to from cements for lunar construction.
The establishment of a permanently manned lunar base requires construction
materials which can withstand the lunar environment and can be obtained from
locally available lunar materials.
New processing techniques must be developed for the low gravity environment,
and durability of the product becomes a more important consideration than
strength from locally available materials.
New processing techniques must be developed for the low gravity environment,
and durability of the product becomes a more important consideration than
strength, since the material will be subjected to widely varying thermal
extremes and constant exposure to solar radiation.
Hays and Walker (1975) have inferred that the lunar dust consist of cumulus
plagioclase with entrapped olivine, low-calcium pyroxene, and magnesium and
aluminum-rich spinal. Since these igneous minerals are extremely durable and
the evidence suggests that the regolith is derived from weathering of the
underlying crust, it can be inferred that, unless underground construction
is elected, lunar building materials will be subjected to more rigorous
conditions than any on earth.
The lunar crust, estimated to be thick (Toksoz..., 1974) is covered by
continuous layer of mineral debris, or soil, called regolith.
The main constituents of lunar regolith are the same oxides found in
Portland cement and blast-furnace slag, but in different proportions. The
average chemical composition of the fine-grained regolith at various is
given in Table 1 (from Taylar, 1982).
Table 1 - Chemical constitution of lunar soil:....
There is a significant amount of glassy material due mostly to melting
during meteorite impact. Most of this material exists in the form of
agglutinates-glass-bonded aggregates of glassy, rock and mineral fragment,
formed by during micrometeorite impact.
Taking into account mineral and the chemical similarity of lunar grounds and
aluminosilicate components (blast furnace slag's) alkaline binding systems
is possible to per forward the supposition about expediency use of known
principles of a construction alkaline binding systems for obtaining binding
substances and building materials on the basis of lunar grounds.
Alkaline binding materials were suggested by Prof..Glukhowsky in 1957 now
this work continue in Our Group.
The concrete were called "soil silicate concrete's", and the binders "soil
cement". The soil cements are obtained by mixing well-ground mountain rock
with industrial wastes dissolved in caustic alkalis and salt of sodium and
potassium. They are modeling the formation of natural zeolites of the type
R2O'RO'R2O3'(2-4)SiO2 x nH2O. The synthesizing of these materials,i.e. their
solidifying in the earth's crust, like zeolites, mica, hydrous mica, which
at high temperatures crystallize to nepheline and feldspars. The synthetic
process is similar to the natural processes of mineral and rock formation.
the idea of using such minerals in binding systems is associated with the
fact that the earth'crust is mainly composed of the rock-forming minerals
based on calcium-sodium-potassium-aluminosilicates, with remarkable
properties, above all high resistance to atmospheric agents. It is assumed
that compounds of a similar nature can be synthesized in the same conditions
as the present binders of hydrated solidification solidify and harden.
Studies have shown that soluble compounds of alkaline metals (caustic
alkali, non-silicate, silicates and aluminates) in conjunction with
aluminosilicate systems, in which calcium is absent (certain slags and
ashes, burnt rock and clay), and with calcium binding systems (lime,
Portland and alumina cements, blast furnace slag's and high-content calcium
ashes and slag's) from hydraulic binding systems called soil cements, which
solidify and harden in water,under ordinary and natural conditions, by steam
treatment and in autoclave.
The compressive strength of slag-alkaline binders is in the range of 40 to
120 Mpa, those of high strength reaching 150 Mps. The slag-alkaline binders
have great heat resistance and resistance to aggressive weather conditions,
low shrinkage, heat loss and contraction.
Their products of hydration are low-basic hydrous calcium silicate,
calcite, silica, a blend of alkali-alkaline soil hydrous silicates, and
aliminosilicates and hydrous alumina-silica of type tompsonite, hydrous
hepheline, analcime, muscovite and others.
Rapid-hardening slag-alkaline concrete's are known for their intensity in
attaining strength: in one day
30 Mpa, at a specific surface of 450 to 500 m2/kg up to 60 to 70 Mpa, in two
days 40 to 50 Mpa, in three days 50 to 60 Mpa, and in 28 days 70 to 150 Mpa.
For period of development of the scientific bases (fundamentals) of a
construction of alkaline binders systems since 1957. More 1000 scientific
activities are published switching on 14 monographs, more than 350
ampere-second is obtained. USSR and 10 international patents, is developed a
full package (packet) of the normative - engineering specifications and is
conducted 3 national and 2 international conferences on a problem of
development alkaline binders and concrete.

The interesting information on all affected problems can be received to
the address of my group.