Short-term Test Methods Research Articles

Investigation and optimization of short-term aging test conditions for asphalt binders

The existing short-term aging test methods have disadvantages such as not being suitable for high viscosity modified asphalt, different aging degrees between them and poor testing convenience. Therefore, this paper investigated and optimized the aging test conditions of asphalt. The macroscopic rheology and microchemistry of aged asphalt prepared by different aging conditions were comprehensively evaluated. Finally, the most suitable aging test conditions for asphalt was determined by referring to the aging degree of loose asphalt mixture. The experiment results showed that after aging, the rutting factor, carbonyl index, asphaltene content, and creep stiffness of asphalt would increase. The aging degree of existing asphalt aging methods (TFOT and RTFOT) and the corresponding loose asphalt mixture was quite different, and the difference percentage could reach 86.6%. Based on the TFOT test, the asphalt aging conditions were optimized. The aging temperature was 163 ℃. For 70# and SBS modified asphalt, the recommended asphalt film thickness and aging time were 1.59 mm–85 min and 0.80 mm–85 min, respectively. The aging degree of high viscosity modified asphalt under the condition of 0.80 mm–85 min was close to the aging degree of loose asphalt mixture at 135 ℃, and the aging degree of 0.80 mm–100 min was close to the aging degree of loose asphalt mixture at 165 ℃. The proposed aging test conditions can not only accurately simulate the short-term aging behavior of asphalt, but also shorten aging time and save resources.

Experimental study on structural adhesive properties of aluminum plate and carbon fiber-reinforced polymer heterogeneous materials

Structural adhesive bonding between aluminum and carbon fiber-reinforced polymer (CFRP) is an important part of the vehicle's lightweight design and must ensure high strength and durability during the life of the structural member. The paper presents a precise assessment scheme to accurately and reliably infer the performance of adhesive joints through a short-term experimental test method that focuses on intrinsic and extrinsic factors affecting bond strength. The experimental results show that the surface of CFRP is polished, which is beneficial to improve the bonding quality, and the damage type transitioned from adhesion damage to substrate or cohesion damage. Aluminum alloy electrophoresis and non-electrophoresis have no significant effect on the bonding performance. Secondly, the design of the bonding nodes should be considered to bring them into a state of shear stress and be able to withstand greater loads. Meanwhile, the moderate thickness of the adhesive layer and increased bonding area serve to enhance bond reliability. In addition, various environments can cause various physical and chemical changes within structural adhesives, which can reduce the cohesive strength and durability of adhesives. This experiment is designed to select process parameters and adhesive applications for structural adhesives, which are crucial in predicting and evaluating the performance of newly developed structural adhesives and bonded joints.

Development of the Galvanic Anode Performance Test for Assessing the Longevity of Galvanic Anodes for Reinforced Concrete Structures

The NACE impact report (2016) states that nearly 50% of reinforced concrete (RC) structures experience major repair in about 10 y. The existing approach of patch repair does not address the root cause and may not be durable—resulting in re-repair and huge economic loss. Galvanic anodes (GAs) are gaining widespread acceptance to achieve maintenance-free repair life for a few decades. However, a few GAs with inadequate characteristics are prematurely failing (within a few months). There are no short-term test methods to evaluate the longevity of GAs. Therefore, this work focuses on developing a short-term test method (galvanic anode performance [GAP] test) to assess the longevity of GAs. For this, the GAP specimen was designed by simulating RC structures protected with cathodic protection systems as follows: (i) GA embedded in bedding mortar (i.e., anode), (ii) nichrome mesh (i.e., cathode simulating rebars in RC structures), (iii) position of anode and cathode, (iv) application of potential difference (0.5 V, 1 V, 5 V, 10 V, 20 V, and 30 V) to accelerate the degradation of GAs, and (v) electrolyte to simulate conductivity of concrete. Applied potentials >5 V could not capture the difference in characteristics of GAs. However, potential differences of 0.5 V, 1 V, and 5 V could show the true behavior of GAs in various exposure conditions. Then, an approach is proposed to evaluate the service life of GAs. Possible reasons for the premature failure of anodes were investigated by evaluating pH and pore volume of encapsulating mortar. The GAP test can help practicing engineers estimate the longevity of GAs.

Bakırçay nehri yüzey sularının Scenedesmus dimorphus yeşil algi gelişimi üzerine etkileri hakkında bir ön çalışma

Bakırçay River, one of the important rivers of the Aegean region, has a length of 129 km and an approximate catchment area of 3160 km2. Bakırçay River, which carries agricultural drainage and polluted wastewater with high nitrogen and phosphorus content, is polluted due to domestic and agricultural resources. The water of the Bakırçay River is used for irrigation in agriculture and fishing from the dam lakes on the river for feeding purposes also negatively affects the health of the people in the vicinity. In the Bakırçay River, there is widespread pollution caused by mining areas as well as domestic, industrial and agricultural pollution. For this purpose, the “Algal Growth Inhibition Test, OECD 201” was applied to the water samples obtained from 10 stations on the Bakırçay River. Scenedesmus dimorphus (Turpin) Kützing, 1834 green algae culture, accepted as the primary trophic level representative for the " Algal Growth Inhibition Test, OECD 201" test, one of the short-term phytotoxicity test methods, was used in this test. Water samples were tested at five different dilutions (40, 60, 80, 100 %). To determine the effects on the growth of Scenedesmus dimorphus, the cells were counted by fluorimeter (Turner design) daily at the same time and the test duration was 72 hours. In conclusion, the highest level of toxicity was found at Stations 1, 9, 10,13,14, and 15. The reason for this was that there was a coal facility near Station 9 and that all branches of the Bakırçay River joined near Station15 and then drained into Çandarlı Bay.

Method Development for a Short-Term 7-Day Toxicity Test with Unionid Mussels.

The US Environmental Protection Agency's short-term freshwater effluent test methods include a fish (Pimephales promelas), a cladoceran (Ceriodaphnia dubia), and a green alga (Raphidocelis subcapitata). There is a recognized need for additional taxa to accompany the three standard species for effluent testing. An appropriate additional taxon is unionid mussels because mussels are widely distributed, live burrowed in sediment and filter particles from the water column for food, and exhibit high sensitivity to a variety of contaminants. Multiple studies were conducted to develop a relevant and robust short-term test method for mussels. We first evaluated the comparative sensitivity of two mussel species (Villosa constricta and Lampsilis siliquoidea) and two standard species (P. promelas and C. dubia) using two mock effluents prepared by mixing ammonia and five metals (cadmium, copper, nickel, lead, and zinc) or a field-collected effluent in 7-day exposures. Both mussel species were equally or more sensitive (more than two-fold) to effluents compared with the standard species. Next, we refined the mussel test method by first determining the best feeding rate of a commercial algal mixture for three age groups (1, 2, and 3 weeks old) of L. siliquoidea in a 7-day feeding experiment, and then used the derived optimal feeding rates to assess the sensitivity of the three ages of juveniles in a 7-day reference toxicant (sodium chloride [NaCl]) test. Juvenile mussels grew substantially (30%-52% length increase) when the 1- or 2-week-old mussels were fed 2 ml twice daily and the 3-week-old mussels were fed 3 ml twice daily. The 25% inhibition concentrations (IC25s) for NaCl were similar (314-520 mg Cl/L) among the three age groups, indicating that an age range of 1- to 3-week-old mussels can be used for a 7-day test. Finally, using the refined test method, we conducted an interlaboratory study among 13 laboratories to evaluate the performance of a 7-day NaCl test with L. siliquoidea. Eleven laboratories successfully completed the test, with more than 80% control survival and reliable growth data. The IC25s ranged from 296 to 1076 mg Cl/L, with a low (34%) coefficient of variation, indicating that the proposed method for L. siliquoidea has acceptable precision. Environ Toxicol Chem 2021;40:3392-3409. © 2021 SETAC.

Parametric optimization of face turning parameters for surface roughness on EN 31 material using RSM and Taguchi method

In order to improve the product quality process parameters, play a very important role. The industries are in requirement of producing more components with adequate quality with minimum time and amount. In the present day requirement of high carbon steels are increasing as the strength of high carbon steel is high as these are mostly used in the industries, as its applications are very vast. In the attempt EN 31 steel is used. L27 orthogonal array used to conduct DOE to study the effect of process parameters like Speed, feed, depth of cut and nose radius on surface roughness were found. For each parameter 3 levels are considered. To conduct experiments CNC lathe machine and to find surface roughness tally surface instrument were used. In this prospects the authors made an attempt and proposed the optimized process parameters. Face turning operation is proved short term test method for identifying machinability and optimized process parameter. The results showed that the optimal values obtained by RSM method are speed 1214.414 RPM, feed 0.050 mm/rev, Depth of Cut 0.1 mm and nose Radius as 0.4 mm. the optimal value predicted by RSSM is shown good correlation with experimental one.

Comparison of short- and long-term ASR test methods on cementitious composites

Concrete has a significant place in construction structures, is a material that can be easily damaged due to incorrect design, incorrect material selection. Concrete may be damaged by physical and chemical factors. One of these factors is the alkali-silica reaction (ASR). ASTM C1260, is a short-term test method, and ASTM C227, is a long-term test method, are used to measure effect of alkali-silica reaction. In this study, the effect of fly ash additive use with 0, 5, 10, 15, and 20 wt.% replacement of cement was investigated in short- and long-term ASR test methods. For this purpose, while samples prepared for ASTM C1260 were kept in NaOH solution 14-days, samples prepared for ASTM C227 were waited 360-days in normal water solution. As a result; mortar bars with 20% fly ash additive ratio were classified as harmless for ASR in both test methods.

Effects of Seating Load Magnitude on Incremental Cyclic Fretting Corrosion in 5°40’ Mixed Alloy Modular Taper Junctions

BackgroundMechanically assisted crevice corrosion of modular tapers continues to be a concern in total joint arthroplasties. A surgical factor that may affect taper fretting corrosion during cyclic loading is seating load magnitude. In this study, modular head-neck taper junctions were seated, capturing load-displacement, over a range of axially oriented loads, and electrochemical and micromotion data were captured during short-term incremental cyclic fretting corrosion (ICFC) tests. The hypothesis is low seating loads result in greater motion and fretting corrosion in ICFC tests. The effect of assembly load on pull-off force post-ICFC testing was also evaluated. MethodsThe study employed custom-built test fixtures which measured head-neck micromotion and an electrochemical chamber to monitor electrochemical reactions. Head-neck motion measurements were captured using 2 noncontact differential variable reluctance transducers mounted to the head. Seating experiments ranged from 1000 to 8000 N. ResultsSignificant differences due to seating loads were reported in seating displacement, ICFC subsidence, and fretting current at 4000 N cyclic load. Seating load decreased but did not eliminate currents. Fretting onset load remained fixed (approximately 1200 N) for tapers seated above 2000 N. Fretting subsidence was negligible for seating loads of 4000 N or higher, and increased subsidence was observed below 4000 N. ConclusionThis short-term test method evaluated the acute performance of modular implants which were assembled under various loads and demonstrated the link between seating loads, fretting motions, and electrochemical reactions. While increased seating loads reduced fretting corrosion and taper subsidence, it did not prevent fretting corrosion even at 8 kN seating.

A short-term test method to determine the chloride threshold of steel–cementitious systems with corrosion inhibiting admixtures

Now-a-days, multiple types of corrosion inhibiting admixtures (CIAs) are being used to enhance the chloride threshold (Clth) of steel–cementitious systems. However, due to the application of external potential to drive chlorides, some existing short-term test methods are not suitable to assess the Clth of S–C systems with CIAs containing anions. This paper presents the development of a Modified Accelerated Chloride Threshold (mACT) test to determine the Clth for S–C systems with CIAs. The test specimens consisted of a mortar cylinder with an embedded steel piece and electrodes forming a 3-electrode corrosion cell. The specimens were exposed to chloride solution and the linear polarization resistance tests were conducted every 3.5 days. The corrosion initiation was detected using statistical analysis of the repeated R p measurements. After corrosion initiation, the chloride content in mortar adjacent to the embedded steel piece was determined and defined as Clth. The time required to complete mACT test for an S–C system with CIAs is about 120 days. The Clth of eight specimens each with S–C system containing (i) without inhibitor, (ii) anodic inhibitor [calcium nitrite] and (iii) bipolar inhibitor [both calcium nitrite and amino alcohol] were determined. Both anodic and bipolar CIAs showed enhanced corrosion resistance. Also, the bipolar inhibitor performed better than anodic inhibitor. It was concluded that the use of CIAs could significantly delay the initiation of chloride-induced corrosion. The mACT test can be used to determine the Clth and estimate the service life during the planning and design stages of a project and help select durable materials.

Performance of thermally modified wood during 14 years of outdoor exposure

The long-term outdoor performance of thermally modified timber (TMT) from four different industrial heat treatment processes was investigated. Graveyard tests (in-ground exposure, use class (UC) 4) and horizontal double layer tests (above ground, UC 3.2) with and without artificial shading were performed. Results from field tests after 14 years of exposure are compared with results from short-term laboratory tests with pure cultures of wood-destroying basidiomycetes and terrestrial microcosms (TMC). The thermally modified material used in the study was: Plato wood (Norway spruce, Picea abies, NL), Thermowood (Scots pine, Pinus sylvestris, FI), New Option Wood (NOW, Maritime pine, Pinus maritima, F), and oil-heat treated (OHT) wood (Scots pine, DE). In addition, Scots pine sapwood and heartwood, Douglas fir (Pseudotsuga menziesii), Sessile oak (Quercus petraea), and CCB treated Scots pine sapwood (0.7 and 2.8% CCB) were examined as control and reference materials. Based on results from laboratory standard tests with brown and white rot causing basidiomycetes all thermally modified materials were classified as durable to slightly durable (durability class (DC) 2–4). In TMC tests with unsterile soil against soft rot and other soil-inhabiting micro-organisms all TMT were classified as durable (DC 2). Consequently, all TMT showed remarkably increased durability compared to the untreated controls (DC 5) and reference species (DC 3–5). In contrast, according to the results of the graveyard tests all four TMTs were classified less durable (DC 4) as well as Douglas fir and Sessile oak. Also exposure above ground in horizontal double layers led to a significantly worse durability compared to the one calculated on the basis of lab test results: Plato, Thermowood, and NOW were classified as ‘less durable’ (DC 4), OHT performed significantly better. Since not all specimens had failed its durability was preliminarily classified as ‘very durable’ (DC 1). On the basis of 14 years outdoor testing under different exposure conditions durability of four industrially produced TMTs turned out to be clearly less than lab test results indicated. Neither in-ground nor above ground performance met the expectations based on testing with basidiomycete cultures and TMCs. Therefore, short-term durability test methods need improvements regarding their predictive capability for modified wood. In summary, the use of TMT in ground as well as under severe above ground conditions cannot be recommended based on the findings from this field test study.

Effect of fiber-matrix adhesion on the creep behavior of CF/PPS composites: temperature and physical aging characterization.

The influence of fiber-matrix adhesion on the linear viscoelastic creep behavior of ‘as received’ and ‘surface modified’ carbon fibers (AR-CF and SM-CF, respectively) reinforced polyphenylene sulfide (PPS) composite materials was investigated. Short-term tensile creep tests were performed on ±45° specimens under six different isothermal conditions, 40, 50, 60, 65, 70 and 75 °C. Physical aging effects were evaluated on both systems using the short-term test method established by Struik. The results showed that the shapes of the curves were affected neither by physical aging nor by the test temperature, allowing then superposition to be made. A unified model was proposed with a single physical aging and temperature-dependent shift factor, a_{T,te}. It was suggested that the surface treatment carried out in SM-CF/PPS had two major effects on the creep response of CF/PPS composites at a reference temperature of 40 °C: a lowering of the initial compliance of about 25 % and a slowing down of the creep response of about 1.1 decade.

The history, development and the present status of the radon measurement programme in the United States of America.

The US radon measurement programme began in the late 1950s by the US Public Health Service in Colorado, New Mexico and Utah during the uranium frenzy. After the 1967 Congressional Hearings on the working conditions in uranium mines, the US Atomic Energy Commission (AEC) was asked to conduct studies in active uranium mines to assess the exposure of the miners on the Colorado Plateau and in New Mexico. From 1967 to 1972, the Health and Safety Laboratory of the US AEC in New York investigated more than 20 uranium mines for radon and radon decay product concentrations and particle size in 4 large uranium mines in New Mexico. In 1970, the US Environmental Protection Agency (EPA) was established and took over some of the AEC radon measurement activities. Between 1975 and 1978, the Environmental Measurements Laboratory of the US Department of Energy conducted the first detailed indoor radon survey in the USA. Later in 1984, the very high concentrations of radon found in Pennsylvania homes set the wheels in motion and gave birth to the US Radon Industry. The US EPA expanded its involvement in radon issues and assumed an active role by establishing the National Radon Proficiency Program to evaluate the effectiveness of radon measurement and mitigation methods. In 1998, due to limited resources EPA privatised the radon programme. This paper presents a personal perspective of past events and current status of the US radon programme. It will present an update on radon health effects, the incidence rate of lung cancer in the USA and the number of radon measurements made from 1988 to 2013 using short-term test methods. More than 23 million measurements were made in the last 25 y and as a result more than 1.24 million homes were mitigated successfully. It is estimated that <2 % of the radon measurements performed in the USA are made using long-term testing devices. The number of homes above the US action level of 148 Bq m(-3) (4 pCi l(-1)) may be ∼8.5 million because ∼50 million homes were added since 1990 to the home inventory. This paper will discuss the current instruments and methods used to measure radon in the USA, and what is the effectiveness of radon resistant new construction, the current status of mitigation standards and the proposed testing protocols in schools and large buildings.

The development of accelerated test methods to evaluate the durability of framing timber

Various accelerated decay resistance trials, including small simulated wall units, samples exposed in enclosed tanks and ‘I’ samples in stacks, have been explored and used to test the durability of treated and untreated radiata pine framing at Scion since 2001. These testing methods have been established to determine the effectiveness of commercial formulations in preventing decay in framing subjected to intermittent wetting. These are relatively short term test methods requiring a minimum of 12 months testing.Results of these tests have been used to develop suitable preservative formulations and retentions for Hazard Class H1.2 for inclusion in New Zealand Standard for Chemical Preservation of Round and Sawn Timber (NZS, 3640). In New Zealand framing hazard Class H1.2 is for timber that is protected from the weather but with a risk of wood reaching a moisture content conductive to decay.In this communication, we discuss the advantages and disadvantages of these test methods.

The Interlaminar Shear Strength Test of Helical Wound Glass Fibre Reinforced Epoxy Laminates Subjected to Hydrothermal Ageing

This paper presents the experimental investigation of interlaminar shear strength (ILSS) tests of helical wound glass fibre reinforced epoxy (GRE) pipes subjected to hydrothermal ageing. Currently, the test is being used by composite pipes manufacturers as the alternative internal quality monitoring program for detection of manufacturing changes and reconfirmation of the design basis of composite pipes. The test specimens were cut in hoop direction from helically wound GRE composite pipes after exposure of 0, 250, 500, 1000-hour water at 80°C. The ILSS tests of the GRE samples were then conducted in accordance with ASTM D2344, and the results were analyzed to evaluate the durability performance of the laminates. The results show a clear degradation in the bonding strength between fibres and resin system interface after 500-1000-hour water exposure at 80°C. This findings show a good agreement in the trend observed with the standard qualification procedure elucidated in ASTM D2992 standard. Hence, ILSS test shows a great potential to be used as the internal short-term mechanical test method to qualify a new resin, curing agent or glass fibre in accordance to the next approach.

Influence of microstructure and surface treatment on the corrosion resistance of martensitic stainless steels 1.4116, 1.4034, and 1.4021

In the last years, new approaches for the evaluation of the corrosion resistance of martensitic stainless steels were developed, which allow nearly non-destructive as well as short-term corrosion testing. This work analyzes the sensitive influence of microstructure and surface treatment on the corrosion resistance. The effect of alloy composition and microstructure, which is always present in addition to the influence of various surface treatments will be evaluated and discussed. The corrosion behavior was investigated with conventional evaluation of the pitting potential, electrochemical potentiodynamic reactivation (EPR), electrochemical noise (EN), and the “KorroPad” (KP) technique. EPR provided information about the passivation ability and the extent of chromium content reduction due to chromium carbide precipitation in the microstructure. The use of EN and KP aims to detect the influence of different surface treatment parameters on the corrosion resistance in a nearly non-destructive way. Furthermore the results shall demonstrate the functionality and convenience of the short-term corrosion test methods EN and KP in order to gain more acceptance within the scientific community. The results will allow the extraction of surface treatment effects on the corrosion behavior of the martensitic stainless steels 1.4116, 1.4034, and 1.4021.

Time dependent chloride diffusion coefficient in concrete

In order to study how to correctly apply the two different time dependencies to service life prediction models, the definition of parameters in the time dependent equation using the long-term test method and the short-term test method, and its relationship were discussed. The experimental results show that, as the two time dependencies have different meanings, they have different manners when handled in service life prediction models. Time dependency of chloride diffusion coefficients in concrete was obtained by fitting experimental data. A large number of accurate experimental data were required to fit the formula of time dependency to ensure the accuracy of service life prediction model.

Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill

This response follows on from a recent discussion by Sánchez (2009) on test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill. Test methods to assess the biodegradability/biodegradable content of organic waste are of great interest across Europe for different purposes, such as landfill acceptance criteria, monitoring treatment facility performance and for monitoring the diversion of biodegradable municipal waste (BMW) from landfill. Many studies have recently attempted to correlate short-term test methods with long-term anaerobic test methods. This response discusses recent findings and conclusions made by Sánchez (2009) and describes recent work undertaken at Cranfield University to develop the enzymatic hydrolysis test (EHT) method. The EHT has previously shown potential as a short-term, non-biological, biodegradability assessment tool, however there is a requirement to further develop this test method. We conclude that aerobic and anaerobic biological test methods are not the only suitable methods of assessing waste treatment process performance; and that alternative methods such as EHT are feasible and potentially suitable.

Isothermal physical aging characterization of Polyether-ether-ketone (PEEK) and Polyphenylene sulfide (PPS) films by creep and stress relaxation

This paper considers the experimental characterization of isothermal physical aging of PEEK and PPS films using a dynamic mechanical analyzer. Using the short-term test method established by Struik, momentary creep and stress relaxation curves were measured at several temperatures within 15–35°C below the glass transition temperature (Tg) at various aging times. Stress and strain levels were such that the materials remained in the linear viscoelastic regime. These curves were then shifted together to determine momentary master curves and shift rates using the PHYAGE program. In order to validate the obtained isothermal physical aging behavior, the results of creep and stress relaxation testing were compared and shown to be consistent with one another using appropriate interconversion of the viscoelastic material functions. Time–temperature superposition of the master curves was also performed. The temperature shift factors and aging shift rates for both PEEK and PPS were consistent for both creep and stress relaxation test results.

FUNDAMENTAL FLAWS IN EPA'S WET VALIDATION APPROACH REVEALED: WET TEST VARIABILITY IS FAR WORSE THAN CHEMICAL METHODS

The United States Environmental Protection Agency (EPA) has adopted short-term chronic whole effluent toxicity test methods (the chronic WET test) for use in monitoring compliance with effluent limitations. These methods are reported by EPA to be similar in inter-laboratory test variability to the test methods adopted for chemical parameters (see Final Report: Interlaboratory Variability Study of EPA Short-term Chronic and Acute Whole Effluent Toxicity Test Methods, Vol. 1). This paper reviews in part the technical basis upon which EPA made its assertion and demonstrates test variability far exceeds that estimated by EPA.

Bioassay selection, experimental design and quality control/assurance for use in effluent assessment and control.

In the UK Direct Toxicity Assessment Programme, carried out in 1998-2000, a series of internationally recognised short-term toxicity test methods for algae, invertebrates and fishes, and rapid methods (ECLOX and Microtox) were used extensively. Abbreviated versions of conventional tests (algal growth inhibition tests, Daphnia magna immobilisation test and the oyster embryo-larval development test) were valuable for toxicity screening of effluent discharges and the identification of causes and sources of toxicity. Rapid methods based on chemiluminescence and bioluminescence were not generally useful in this programme, but may have a role where the rapid test has been shown to be an acceptable surrogate for a standardised test method. A range of quality assurance and control measures were identified. Requirements for quality control/assurance are most stringent when deriving data for characterising the toxic hazards of effluents and monitoring compliance against a toxicity reduction target. Lower quality control/assurance requirements can be applied to discharge screening and the identification of causes and sources of toxicity.