Permeability of Coral Concrete


Book Description

The water permeability of hardened coral concrete was investigated to learn the effects of mix design factors. The independent variables were aggregate type and source, watercement ratio, cement content, and pozzolanic admixture. The test data demonstrated that the least permeable coral concrete contained Eniwetok aggregate and after 3 months exposure had a coefficient of permeability approximating 0.000001 inches per hour for the liquid phase and approximating 0.000005 pounds per square inch per hour for the vapor phase. These values were equivalent, for all practical purposes, to the corresponding coefficients of the least permeable reference concrete. The least permeable coral concrete had a gross water-cement ratio not exceeding 5.4 gallons of water per bag of cement and a cement factor of 9.0 bags per cubic yard of concrete. The use of calcined opaline shale, as a partial replacement of portland cement, served to make the coral concrete test specimens stronger, more watertight, and more damp-proof than was otherwise possible, all other factors being equal. (Author).







Investigation of Cement for Concrete to be Used in Structures Near Seawater


Book Description

The paper deals with experimental research concerning the use of cement with the addition of slag when preparing concrete with certain desired properties. Shown are results of experimental research using cement with the addition of 20% slag, crushed aggregate, water, and admixtures, and one high-range water reducer and one "water-proofer" in order to obtain water resistant concrete of high compactness and high strength. The concrete obtained satisfied the desired conditions, using the admixtures, having a low water cement ratio (W/C) but having very good workability. The second part of paper deals with the determination of cement resistance to aggressive water. Since a cement with a sufficiently low percentage of tricalcium aluminate necessary to be resistant to seawater is not always available, we suggest the use of concrete of the highest obtainable density. The coefficient of seawater resistance is obtained by comparing the flexural strength of specimens cured for six months in ordinary water and specimens cured in simulated seawater solution for the same period of time. A higher coefficient of resistance is obtained on specimens with a low W/C, using admixtures compared to those without admixtures, both being of the same consistency in spite of the usage of cement containing a higher percentage of tricalcium aluminate.







Report of the Northern Great Plains Field Station for the 10-year Period, 1913-1922, Inclusive


Book Description

The purpose of this report is to discuss briefly the experiments conducted at the Northern Great Plains Field Station, located in Morton County, North Dakota, two miles south of Mandan. No attempt is made to describe the experiments in detail, but rather to present the lines and scope of the work at the station and give a summary of results obtained from the various experiments. The projects are grouped and divided into three departments: arboriculture, horticulture, and agronomy. The cooperative grazing experiment is a coordinate part of the agronomic work. The work and results are reported separately by the men in charge of the respective departments.




Proceedings of the 7th International Conference on Civil Engineering


Book Description

This book contains research papers presented at the 7th International Conference on Civil Engineering, which was held in Singapore from 24-26 March 2023. Significant results contained in the book show the importance of technology in solving engineering issues throughout the world. Highlighted topics include climate change, disaster relief, resilience, pollution control and management techniques for construction, mitigation and adaptation. Many techniques are utilized in a variety of contexts to solve engineering and urban management problems in both developed and developing countries. This volume consists of refereed submissions authored by a wide variety of international researchers and practitioners from many perspectives discussing emerging issues in civil and environmental engineering. Practical solutions to worldwide issues in hazard mitigation, pollution control, transportation infrastructure and energy production are emphasized. The chapters provide an in-depth look at current issues in these areas of engineering that should benefit interested individuals at all levels of expertise.