A Study of the Effect of Blended Cements on the Durability of Concrete Incorporating an Inferior Coarse Aggregate

Research Project C-13 was set up for the purpose of studying the effect of blended cement, with air-entraining properties, on the durability of concrete incorporating an inferior grade of limestone as the coarse aggregate. This investigation is not correlated with any Department of Highways field project, being entirely a laboratory study. The tests were begun April 12, 1945, and were completed February 6, 1946

Durability of Concrete as Affected by Absorbed Moisture in Tennessee River Gravel Aggregate

This project is more or less a preliminary investigation of Tennessee River gravel relative to the effect of the moisture condition of the aggregates upon the durability of concrete. Certain observations made in the field indicated that absorbed moisture in the aggregate could have a marked effect on concrete, so this study was made in an attempt to give quantitative significance to the observation

Aerosol seeding systems for the NSWC wind tunnels

Four types of laskin nozzles which are used to generate the primary aerosol mist are illustrated. This mist may be used directly as laser doppler velocimeters (LDV) particles. However, in general, a wide range of particle size exists at this stage and requires the use of some type of mono-dispersion refinement technique. These nozzles rely on the shearing action of high speed air near a column of seeding liquid. Typically, olive oil or dioctyl phthalate (DOP) is used, but within the past year solid polystyrene particles in an alcohol suspension have been used with great success. Air, at a typical pressure of five psig, is supplied to the top of the nozzle which is merely a hollow tube. This air issues radially from one or more small jets located near the collar close to the bottom of the tube. When the collar is submerged in the seeding liquid, the hollow columns located in the collar become filled with liquid. The air from the jet shears the liquid into the fine mist

A Study of the Effect of Blended Coarse Aggregate on Air-Entrained Concrete Progress Report 3

The purpose of this investigetion was to study the durability characteristics of a river gravel, used as coarse aggregate for concrete, with respect to four major fractions separated in accordance to their general mineralogical classification. This aggregate was from the same stock of Ohio River gravel that was used in earlier phases of this Project reported in 1947. Since this gravel consisted of several rock types varying in mineralogic constituents, it was conceivable that poor performance could possibly be attributed to some undesirable fraction or fractions, rather than to the aggregate as a whole. The separation of this aggregate was rather general yet satisfactory for the purposes of this study and was confined to four fractions in each of which there was a preponderance of one general rock type. These four fractions were designated, for convenience, as limestone, chert, quartzite, and granite. Evaluation of durability characteristics was made by means of freezing and thawing tests on like samples of concrete made with the different gravel components. All other features of the concrete were kept as constant as possible

Cooperative Investigation of Joint Spacing in Concrete Pavements

During the summer of 1940 the Kentucky Department of Highways, with the Public Roads Administration participating, constructed 6.27 miles of investigational pavement as a cooperative research project on joint spacing. This project was one of six planned by the Public Roads Administration and the Portland Cement Association in cooperation with six highway departments. The five other states participating were California, Michigan, Hinnesota, Missouri, and Oregon. The project selected for this jointing study in Kentucky is in Daviess County, approximately six miles southeast of Owensboro, on Kentucky Route No. 71 (Layout map in Figure 1). The experimental program was outlined for the purpose of evaluating the relative merits of varying intervals in expansion joint spacing and of dummy contraction joints with and without dowel bars for load transfer. A complete discussion of the scope and purpose has been given in a paper by Mr. E. F. Kelly of the Public Roads Administration

An Investigation of Lean Concrete Mixes as Base Courses for Bituminous Surfaces [Jan. 1951]

Cement concrete bases for pavements with bituminous surfaces are, of course, not new. However, it has been many years since concrete has served this purpose except as a pavement itself ultimately resurfaced after years of service. The outstanding qualities of many roads which developed in this way were obvious without any particular tests, and for many years there apparently was no attempt to evaluate them. Probably structural value was first investigated in tests on airfields in Florida, Ohio and California. Although the original concrete pavements in all cases were heavy in comparison with highway sections, the results of the tests have some bearing on highway considerations. In beefing up rigid pavements that had failed under heavy loads and running subsequent tests under moving wheels, the Army Engineers came to the conclusion that --treatments of as little as 3 inches of asphaltic concrete give astounding structural benefits. Accelerated traffic tests have shown overlays of less rigid material to be so beneficial that original designs utilizing a rigid slab of moderate thickness covered with a flexible type surface can and probably will be in cost competition where conditions are favorable

A Study of the Effect of Fine Aggregates on the Durability of Concrete

Research Projects C-14 and C-15 were set up as purely laboratory studies with the same objective; that is, to study the affect upon the strength and durability of normal portland cement concrete by supplementing portions of standard concrete sand with variable amounts of Fine sand (sands passing Size No. 30 sieve). This investigation is not correlated with any Highway Department field projects. Project C-14 was begun June 16, 1944 and test completed April 20, 1945. Project C-15 was begun August 2, 1944 and tests were completed August 1, 1945

Progress Report on Experimental Jointing Installations for Concrete Pavements

Combined in this report are descriptions of the progress of three individual experimental joint installations. Each of these includes a series of two or more experimental joints of special design, installed in concrete pavement in lieu of the conventional types employed in their respective construction projects. These experimental joints included at one location a prefabricated neoprene seal; and, at two locations, aluminum load transfer devices, All installations were contraction joints only, Periodic inspections of these have been made and will be continued on two of the projects until adequate performance records are established. The condition of concrete about the joints with neoprene seals has reached the stage where there would be little value in additional observations

Determination of Unit Weights of Aggregates in the Laboratory and at the Source

As a result of meetings with producers, a committee of Highway Department engineers recommended that a study be made of various type of aggregates from statewide sources; the objective being to arrive at a standard of evaluating unit weight of aggregates of various but commonly recognized characteristics. It was further desired that a factor be determined which could be applied to a given aggregate for computing its unit weight with reasonable accuracy; taking cognizance of specific gravities and densities as influenced by particle shapes and gradation