Immersion-compression test

The Marshall design method (AASHTO T-245) in concert with the Immersion-Compression test (AASHTO T-165 and T-167) were selected by FHWA for the design of Sulphlex-233 paving mixtures... 

No precise correlation is available between the immersion-compression test and results to be expected from pavements in the field. The test provides comparative guidance on water damage susceptibility. For the diabase aggregate, the Sulphlex-233 mixtures measured dry, and after immersign in the case of wet specimens, exceed the 300 psi (2.07 x 10 pascal) minimum compressive strength usually considered necessary for acceptable mixture performance in the field. Retained strengths generally fall below the 70 percent criterion considered acceptable for asphaltic mixtures. 

These tests indicated that sulfur-infiltrated concrete still loses abundant sulfur when immersed in neutral and sulfatic solutions, even though the reaction is localized and relatively slow. Compression tests of a few cylinders showed there had been little reduction in strength over several months. Examination of sawn surfaces revealed no clearly leached zone, but the specimens had turned a mottled blue, except near the center. Faint peripheral fractures had developed, and coherence of the infiltrated matrix near the surface had decreased, suggesting that some leaching had taken place. 

Three samples of RubCon were made for each term of exposure. Before immersing in the medium, samples were measured and weighed. After reaction of the corrosion reagents with RubCon, the samples were taken out of the exicators, dried with filtering paper, and put on a compression test with a speed of 60 MPa/min. 

Stability. Compression test, following the generator of a semi-hooped test sample, after 30 minutes immersion in water at 60°C. Application speed = 0.86 mm/sec. Bend radius of the machines = 50.8 mm. 

In BS 2782, Methods I3IC and D [178], test pieces are heat aged and then crushed in a universal testing machine. For method C, test pieces are molded cylinders or cubes with the principal dimensions set to 10 mm for method D, cubes of side 10 mm are cut from the sheet or molding. Duplicate test pieces are heated to I35 C for 17 hours, followed by a further 6 hours at HO C, after which they are immersed in a fusible metal bath at 400 C for 30 minutes and then cooled to ambient temperature in a desiccator. The compression test is applied so as to give failure in 30 15 seconds. 

Chemical stability. Chemical stability was determined by immersing the impregnated specimens in various chemicals. At 6 and 12 months after exposure in different media, specimens were removed, dried, and subjected to compression tests. The tests indicated that impregnated specimens are stable to the action of solutions of salts, acids, and alkalis and imstable to the action of concentrated nitric, sulfuric, md hydrochloric adds. The most chemically stable is the acrylic composition. 

There are two typical methods to obtain self-weight collapse settlement in engineering one method is to obtain self-weight collapsibUity coefficient based on indoor compression test and then calculate selfweight collapse settlement based on empirical formula (it is referred to as calculated value ) another method is to perform actual measurement of the self-weight collapse settlement in in-situ immersion test (it is referred to measured value ). 

One approach to the study of solubility is to evaluate the time dependence of the solubilization process, such as is conducted in the dissolution testing of dosage forms [70], In this work, the amount of drug substance that becomes dissolved per unit time under standard conditions is followed. Within the accepted model for pharmaceutical dissolution, the rate-limiting step is the transport of solute away from the interfacial layer at the dissolving solid into the bulk solution. To measure the intrinsic dissolution rate of a drug, the compound is normally compressed into a special die to a condition of zero porosity. The system is immersed into the solvent reservoir, and the concentration monitored as a function of time. Use of this procedure yields a dissolution rate parameter that is intrinsic to the compound under study and that is considered an important parameter in the preformulation process. A critical evaluation of the intrinsic dissolution methodology and interpretation is available [71]. 

In keeping with the general theme of this book, our task is somewhat more difficult inasmuch as we routinely must deal with the effects of water on systems. The tests described in ASTM 3527D are designed to describe the qualities of hydrophobic materials. More often than not, the products that are the subjects of this book will be in moist environments. In many cases, the products will be immersed in water. While the dry tests provide some guidance, it is clear that tensile, compressive, and water flow-through tests are needed to determine and describe the in-service properties of the materials. 

ASTM standard specimens and procedures were used for flexure (D-690), compression (D 695), Izod impact and torsional pendulum analysis (TPA). For tension, D1822 tensile impact specimens were substituted for D638 specimens to conserve material. Test specimens were machined from the plates and cylinders using a water cooled dlamond wheel. All the specimens were dried in vacuo at 100°C for three weeks before testing or subsequent postcure treatment. Half the specimens were post-cured for 2 hours at 225°C in vacuo before testing. Selected specimens were Immersed in distilled water at 80°C for 6 weeks for moisture uptake determinations. 

Accelerated testing was performed by immersing polyurethane liner specimens in water at several elevated temperatures. Periodically, the samples were removed from their respective water baths, dried and then subjected to hardness and compressive stress-strain measurements. An Arrhenius relationship was employed to estimate the expected life of the pads under the severe condition of being continually immersed in water at 35 C. The pads were considered to have failed when their compressive stress fell to 80 percent of the original value. 

Accelerated hydrolytic stability tests Indicate that the polyether-based urethane employed In this study In the preparation of the liner pads can successfully withstand contlntious Immersion In water at 3S C for 24 years. Under such an exposure, the pads are expected to lose approximately 20 percent of their original compressive strength. 

The simplest form of compatibility test is to immerse standard ASTM coupons in a liquid or vapor in the lab. Coupons can be installed in the field in a stream. However making a coupon assembly for installation in a pipe or a vessel may be difficult and persuading plant operators even more so. Lab testing is easy to carry out but will not replicate real life conditions such as flow, agitation, stress (compression for gaskets) and one-sided exposure. For this reason, lab dunk tests are usually done for screening reasons. Application temperature is easy to achieve by space heaters. 

Single (axial) compressive strength. Speed = 1 mm/sec. Test immediately after 7 days dry and after 7 days of immersion. 

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