It has been proposed that a large pressurized shirt sleeve environment assembly facility would be useful during all phases of lunar outpost development. This article discusses the use of such a facility during later phases of outpost development when use of native materials is maximized. The principle benefits from the use of a large pressurized facility are that workers needn't wear cumbersome, restrictive space suits and concrete needn't be cured in the vacuum environment of the moon. A specific assembly facility concept is presented and its conversion to a lunar precast concrete plant is discussed.

An important aspect of lunar concrete production will be the production of lime (CaO) from lunar rocks. Chemical and thermodynamic data show that lime could most easily be distracted from abundant lunar anorthite (CaAl2Si2O8) the major mineral in the anorthositic lunar highlands. If fluorine gas, produced on site by electrolysis of molten NaF, is used as the extracting agent, oxygen, silicon, and aluminum can be recovered at the same time. Of these, oxygen is likely to be the most valuable product. Lime is recovered from fluorite, CaF2, by reaction with soda, Na2O; the resulting NaF is recycled into fluorine production immediately before use. No fluorine gas is transported or stored in this process; it is used up as soon as it is made.

The methodology for forming and placing lunar concretes will incorporate our present technology as well as add the innovations that will be developed in the years to come. Initial habitation will combine the use of inflatable forms, precast modules, and self-contained modules that are landed on the lunar surface. The forming and placing systems used for cast-in-place lunar concrete may include temporary stay-forms, preplaced aggregate concrete (which utilizes injection grouting), air-o-form system, and precast concrete. Lightweight fiberglass formties have great potential for lunar construction. A case history and discussion for preplaced aggregate concrete usage is provided for the Peoria Lock Resurfacing Project. The placement size was 1 ft (0.3048 m) wide x 40 ft (12.2 m) long x 10 ft (3.1 m) deep. The maximum size aggregate was 3 in. (7.6 cm) for increased economy. Typically, the angle of repose for the grout was 1:10. Test results for 7-day and 28-day compressive strengths for 2 in. (5 cm) mortar cubes, preplaced aggregate concrete cylinders, and conventional concrete are given. Other items discussed in the article are concretes for a lunar landing support facility, modified shotcreting and curing methods, and a variety of modified inflatable form structures.

This paper suggests establishing the applicability and manufacturing technique of GFRP, particularly dimethylisophtalate glass-filament rod. The use of GFRP reinforcement in lieu of conventional steel rods and wires has great potential for precast structural concrete elements. GFRP may be cheaper, lighter, and formed from materials found in abundance on earth and on the moon, namely silica (SiO2). GFRP can be manufactured with the same, if not higher, tensile properties of steel. If synergically composed with a plastic carrier, a new science in construction and structural analysis could be born. No doubt remains that lunar soil is cementitious. Rocks for aggregate and silica are also abundant on the moon. Heavy fabricated steel rods are counterproductive for transport to the moon. Glass fibers fabricated on the moon have great potential. Permanent settlement/habitats on the moon are within the realm of possibility and may be considered immediate projects. Therefore, the idea of using local materials is appropriate within the concept of a third phase of permanent underground reinforced concrete construction facilities, the first being the Apollo landings and the second a temporary above-ground lunar establishment yet to come. This analysis could lend itself not only to permanent reinforced concrete structures on the moon, but to any other planet where silica is abundant and cement could become a local product, through refining and reducing appropriate local ores. Manufacture of glass-fiber filaments is incomparably cheaper than steel. Additional research, at a later date, will encompass the application of pre- and post-tensioned GFRP reinforcements, using the same structural form elements. This paper proves the positive applicability of GFRP as reinforcement for precast concrete elements.

Based on the available data on abundance and composition of lunar materials, lunar basalts were selected as a prospective base source for cement production. Methods of increasing calcium content of natural raw materials were developed. The experimental study was conducted in two directions: sintering mixes of natural materials with CaO and activating mineral glasses obtained by beneficiation of the natural rocks. In both cases, the terrestrial materials were selected to simulate the lunar rocks. The sintered cement exhibited properties analogous to those of known portland cements. The vitreous material simulating the composition of beneficiated lunar rocks developed cementitious properties when it was activated by the chemical agent and cured under the conditions of high humidity and elevated temperatures.