Donald E. Kline

The dynamic mechanical behavior of some nylons

Abstract The dynamic mechanical properties of 6-6 nylon, 6–10 nylon, and a nylon copolymer have been studied in the audio-frequency region over a temperature range extending from about 80°K. to near the melting point by driving rodlike samples in their first transverse mode of oscillation. In all nylon types tested, four dispersion regions are observed, the first three being at temperatures of approximately 170°, 250°, and 350°K. These dispersion regions appear both as peaks in the absorption curve and as relatively sharp drops in the resonance frequency curve. The magnitude and temperature positions of the damping maxima are dependent on the specific nylon type. Over parts of the temperature region the damping of 6-6 nylon depends on the thermal history and water content of the sample. Possible assignments for each of the observed dispersion regions in terms of molecular motion are given. Correlations between the dynamic mechanical data and the results of other physical measurements on the nylons are pointed out.

Pore size distribution in epoxy impregnated hardened cement pastes

Abstract Specimens of hardened portland cement paste (Type 1), hydrated for various periods of time, were ovendried and subsequently filled with an epoxy resin system via a vacuum-pressure technique. Data obtained from mercury intrusion porosimetry indicate that a significant amount of porosity is left unfilled by polymer in the more mature (28 days hydration) specimens. Calculations indicate that the smallest micropores ( μ m) are essentially inaccessible to the monomer system used in this study.

Effect of hydration on the mechanical properties of epoxy impregnated concrete

Abstract Following various hydration times (1 to 28 days) concrete was impregnated with an epoxy resin system. For a given impregnation condition (vacuum, pressure and time), it was found that higher polymer loadings were achieved in specimens having shorter hydration times. Compressive modulus and compressive strength values for impregnated specimens were higher than their corresponding control values. Compressive modulus values appear to be a function of hydration time (up to 14 days) for impregnated specimens, but the modulus of 1 day impregnated specimens is considerably higher than that of all the controls (1 to 28 day). Compressive strength values appear to be primarily a function of volume loading, and 1 day impregnated specimens displayed compressive strength values of greater than 10, 000 psi.

Penetration of concrete with various linseed oil/mineral spirits mixtures

Abstract Field impregnation techniques were simulated in the laboratory using concrete cylinders (different water:cement ratios) dried either in a forced air oven or with a gas-fired infrared heater after which they were impregnated (by ponding) with different linseed oil/mineral spirits mixtures. Mass uptake was obtained for impregnation with various mineral spirits concentrations and impregnation temperatures. Generally as the water:cement ratio, impregnation temperature, and mineral spirits concentration increase, the final mass uptake (or rate of mass uptake) and penetration depth also increase. Further, the infrared dried specimens displayed a deeper final penetration depth than the ovendried specimens. Regression analysis produced equations that predict the final penetration depth in the concrete as a function of percent mineral spirits in the linseed oil mixture.

Residual porosity after impregnation of concrete with linseed oil/mineral spirits mixtures

Abstract Pore characteristics of concrete impregnated with boiled linseed oil were investigated using a mercury porosimeter. Prior to impregnations, specimens were dried either in a forced-air oven or with a gas-fired infrared heater. For impregnation, boiled linseed oil was mixed with various amounts of mineral spirits by weight. As the percentage of mineral spirits increased, the total specimen porosity increased, but the total porosity was still lower than that of the unimpregnated controls. Pore size distrubution shifted with impregnation and varied with the percentage of mineral spirits used. Regression analysis revealed relationships between the total intrusion, percent reduction in porosity, and total porosity versus percent boiled linseed oil by weight.

Impregnation of concrete with hot epoxy resins

Abstract Impregnation of concrete with two types of hot epoxy resins was investigated. Compared with the more commonly used acrylics, epoxies offer reduced danger from fumes, fire and explosion. Economic advantages due to the reduction or elimination of the post-drying cool-down period are also afforded by the epoxy. This study revealed that an aliphatic-based epoxy impregnant at 105°C displays an uptake rate approaching that of acrylic monomers. However, the narrow span between the polymerization and degradation temperatures could limit applicability.

Compressive strength of concrete impregnated with epoxy systems that do not contain a curing agent

Concrete impregnated with epoxy was polymerized at high temperature using moisture that remains after controlled drying as a curing agent. Moisture content, impregnation, and polymerization conditions were investigated for concrete test cylinders. Impregnation conditions may have to be adjusted for other concrete systems depending upon thickness of the concrete, maturity of the concrete, and drying conditions. Compressive strength values for this novel system were lower than concrete impregnated with conventional epoxy systems but significantly higher than the controls.

Chloride penetration of concrete impregnated with various linseed oil/mineral spirits combinations

Abstract Concrete test cylinders (3 × 6 in., or 7.6 × 15.2 cm) dried in a forced air oven or with a gas fired infrared heater were impregnated with different boiled linseed oil/mineral spirits mixtures. The impregnated cylinders, along with nonlinseed oil impregnated cylinders, were contaminated with a saturated sodium chloride solution. Chloride content determinations were performed on mortar specimens obtained at various depths from the surface of the cylinders. Chloride contents determined on the controls indicated chloride levels much higher than probably would have occurred in actual field concrete. The data on linseed oil mixture impregnated concrete indicate that chloride ion penetration into the concrete is significantly reduced as compared to the control specimens.

The effects of deicer salts on the pressure impregnation of bridge deck type concrete with methyl methacrylate

Abstract A group of cylindrical concrete specimens, containing various known quantities of deicer salts, were impregnated from the top surface under a pressure of 75 psig (517 KPa) until complete penetration of the concrete (5 in. or 12.7 cm) was achieved. It was found that increasing salt contents, up to 0.75% Cl− by weight of the mortar fraction of the concrete, had no effect on quantity of monomer inbibed, the volume percent of porosity filled with the monomer, nor the degree of water absorptivity of the polymer impregnated concrete. A second group of specimens was impregnated from the top surface at various pressures ranging from 0 to 75 psig (101 to 517 KPa) to a given level of monomer loading. For a given pressure, monomer loading was found to vary directly with the square root of time. Also, it was shown that higher pressures provide denser polymer loadings, higher rates of impregnation, and for a given time period, increased depth of penetration.