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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 21 Abstracts search results
Document:
SP125-17
Date:
May 1, 1991
Author(s):
A. Mishulovich, Tung D. Lin, S. W. Tresouthick, and P. B. West
Publication:
Symposium Papers
Volume:
125
Abstract:
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.
DOI:
10.14359/2450
SP125-18
C. L. Hwang, R. Y. Lin, S. L. Shieh, and L. C. Lee
The quality of concrete construction conventionally relies on the workability and consolidation of the concrete mixture. Practically speaking, the higher the amount of water used, the better the workability of fresh concrete; however, the use of excessive amounts of water will induce some detrimental effects on the quality of concrete. For example, the increase of water content in concrete mix proportions may reduce the bonding strength between cement paste and aggregate interface because of the voids and possibility of bleeding. To deal with this problem, compaction technology is adopted to produce precasted segments. A specific dry concrete mixture containing fly ash is calculated from the minimum-void concept, and the dry mixing method is selected to process the mix. The test results reveal that segments with homogeneous quality and excellent engineering properties can be obtained by a 3-min high-pressure compaction process and 1- to 2-day moist-curing. From experience, the automated process of production is also feasible, and it is proposed that the properties of segment using compaction and similarity technology from this study have great possibilities in lunar base construction.
10.14359/2459
SP125-01
G. D. Nasser
The age of space exploration is already here and it appears likely that, in the next 20 years, there will be permanent bases on the moon. Therefore, it is incumbent upon engineers designing lunar structures to become knowledgeable about the peculiar effects of gravity and relativity under extraterrestrial conditions. The purpose of the paper is to present a review of Newtonian physics in light of Einstein's special and general theories of relativity. In particular, Newton's classic laws of motion and gravitation are compared with modern concepts of space-time, time dilation, length contraction, equivalency principle, and other interesting aspects of relativity.
10.14359/3679
SP125-03
David O. Swint and S. R. Schmidt
The United States Air Force Academy's Engineering 410 class, Spring 1989, tested the feasibility of using concrete as a lunar construction material. This was a continuation of two previous semesters' effort. Concrete specimens were tested by combining different cement types, mixing environments, and additives to determine their effects on strengths and other engineering properties of the specimens. Using 5 different variables, a total of 80 possible combinations existed. The group used a D-optimal design with 18 possible combinations to build a prediction equation to optimize the concrete design mixture. Confirmation tests were conducted on the optimal design and compared with the mathematical algorithm prediction. The results demonstrate the power of this approach in experimentation for concrete applications.
10.14359/3691
SP125-02
Shinji Matsumoto, Tetsuji yoshida, and Kenji Takagi
Lunar base concepts utilizing concrete as structural material have been proposed recently. These are based on the consideration that oxygen and raw materials used in manufacturing cement will be extracted from lunar resources and that the soils and rocks will be used as aggregates of concrete. The moon has an abundance of raw material used in manufacturing cement within its rocky soil, thus requiring rocks to be crushed. The paper discusses a unique rock-breaking system using plentiful solar energy available on the moon: that is, sudden heating of a rock surface induces high thermal stress within the rock, which results in the rock breaking. Appropriate heat flow and radiating time are calculated using the physical property of basalt, which has a similar chemical composition to lunar rock. Additionally, required system volume is estimated.
10.14359/3698
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