Annual Book Of ASTM Standards Research Articles

Accelerated Concrete-Cylinder Test for Alkali–Silica Reaction

Abstract The concrete-prism test (CPT, e.g., ASTM C1293-08b [ASTM C1293-08b: Standard Test Method for Determination of Length Change of Concrete Due to Alkali-Silica Reaction, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2013]) has been considered as the best index for alkali–silica reaction (ASR) field performance, but alkali leaching and test duration are still of concern. Reduction of test duration by increasing testing temperature (e.g., 60°C) was proposed by several researchers to develop an accelerated version of the concrete-prism test (ACPT). However, it has been found that there is a significant reduction in expansion associated with more alkali leaching in the ACPT compared to the concrete-prism test (CPT). An accelerated concrete-cylinder test (ACCT) has been proposed in this study with no involvement of errors because of operation and temperature change along with arresting alkali leaching. The linear expansion of the ACCT measured at a temperature of 60°C over a period of 1 month have been correlated with the 1-yr ASTM C1293 test to evaluate the ASR reactivity of aggregates. Cylinders made with highly reactive borosilicate glass balls were tested first to validate the proposed approach before any concrete-cylinder testing. The results indicate that (1) an expansion limit of 0.04 % using 0.82 % Na2O equivalent (Na2Oe) cement without alkali boosting after a testing period of 28 days is proposed for the ACCT to diagnose ASR aggregate reactivity, and (2) the proposed method can serve as an alternative to validate the ASR-resistant mix design (e.g., fly-ash contents).

Consistency of the Casagrande Liquid Limit Test

The liquid limit test is one of the most widely used tests in soil mechanics, with the value obtained being correlated against a variety of soil properties such as soil strength. The percussion test for liquid limit originally described by Casagrande [Casagrande, A., 1932, “Research on the Atterberg Limits of Soils,” Public Roads, Vol. 13, pp. 121−136] is the standard test for liquid limit in much of the world. The apparatus to be used is described in many design codes including ASTM D4318-10e1 [Standard Test Methods for Liquid Limit, Plastic Limit and Plasticity Index of Soils, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA]. While it is well known that two classes of these devices exist, those with hard and soft bases, the true picture is more complex; international design codes contain a great variety of specifications for the devices, some much more prescriptive than others. This paper uses the analysis described by Haigh (2012) to investigate the effects of base hardness and resilience on specific strength at liquid limit. A survey of devices in use worldwide was also carried out, indicating that both the variability in national design standards and potential degradation of bases over time leads to a large variability in the specific strength observed at liquid limit when different devices are used. The paper demonstrates that both base hardness and resilience must be regularly monitored in order to achieve consistency of liquid limit test results and that international standards should be more closely aligned if measured values are to be used within regressions based on liquid limit tests carried out with apparatus based on a different standard.

Tensile Mechanical Response of Ultra-High-Performance Concrete

Abstract The tensile mechanical response of ultra-high-performance concrete (UHPC) is distinctly different from conventional concretes and traditional fiber-reinforced concretes. UHPC can exhibit a pseudo-strain-hardening behavior wherein the fiber reinforcement bridging tensile cracks is sufficient to allow for a sustained tensile capacity at stress levels near the tensile-matrix-cracking strength through significant tensile-strain levels. This mechanical response is generating interest in the structural design community; however, quantification of the response through standardized test methods is necessary. Researchers at the U.S. Federal Highway Administration have developed a test that directly measures the tensile response of UHPC-class materials. This test, conceptually similar to the ASTM E8 [ASTM E8-13a: Standard Test Methods for Tension Testing of Metallic Materials, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2013] test for steel, provides a method to assess the tensile response from elastic behaviors through multi-cracking and eventual crack localization. Prismatic specimens are loaded in direct tension under a fixed-end condition, allowing cast or extracted specimens to be tested under conditions that mimic the tensile loading that can occur within full-scale structural elements. Testing to date has assessed two UHPC matrices and a variety of fiber types/dosages with promising results in terms of test-procedure robustness.

A Closer Look at Effects of the Loading Rate on Fracture Toughness in the Ductile-to-Brittle Transition Regime of a Ferritic Steel

Abstract An increased loading rate causes not only a shift of the ductile-to-brittle transition curve, but also a slight change of the shape of this curve. The latter tends to become steeper as the loading rate increases. This effect was observed even at loading rates that are considered to be quasi-static according to ASTM E1921-13: Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2013. Actually, the coefficient 0.019 in the exponent of the MC turned out to be substantially higher at elevated loading rates. This means that a basic assumption of the evaluation procedure of ASTM E1921 is not met, which leads to an increased uncertainty of T0 or T0,x, respectively. This effect of is most pronounced in testing at elevated loading rates using the single-temperature option. An improved method to determine the reference temperature is proposed, where the exponent in the median transition curve in ASTM E1921 is considered to be an open parameter. The resulting reference temperatures, denoted as T100 andT100,x, respectively, are expected to be more accurate than standard T0, which is confirmed by comparison with experimental data. Furthermore, the validity requirements for T100 are less restrictive and more suitable than those in ASTM E1921, since they do not depend on the outcome of the tests. Based on the improved data, an improved estimation formula for the rate-induced shift of T0 is derived. Suggestions are made for improvement of ASTM E1921.

Effects of Nanomaterials on the Hydration Kinetics and Rheology of Portland Cement Pastes

Abstract In this paper, effects of nanomaterials on the hydration kinetics and rheology of ordinary Portland cement pastes were investigated. Three nanomaterials, nano-limestone, nano-silica, and nano-clay (a highly purified magnesium aluminosilicate), were added to a cement paste at the levels of 0.0 %, 0.5 %, 1.0 %, and 1.5 % (by mass) of cement. The heat of cement hydration of the paste was measured using isothermal calorimetry. Rheological behavior of the paste was characterized using a rotational rheometer. The rheology measurements were performed at 10, 30, 60, 90, and 120 min after the cement was mixed with water. Set times of the paste were measured according to ASTM C191 [Standard Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA]. The experimental results indicate that the addition of nano-limestone and nano-silica accelerated cement early hydration, the maximum heat flow increased, whereas the time to reach the heat-flow peaks decreased. The initial and final set times were also reduced. These effects were enhanced with increased nano-addition level. The addition of nano-clay also significantly increased the intensity of the heat flow peaks, and, especially, the peak corresponding to the renewed reaction of the aluminate phase. Addition of these nanomaterials generally increased yield stress and viscosity of the cement paste, especially after 60 min when cement hydration started to accelerate. Nano-clay considerably influenced the rheological behavior of the cement paste. Significantly higher shear stresses were required to initiate the flow.

Applications of the New Approach to Resonant Column Testing

For more than 50 years, the resonant column test has been used to measure the shear modulus and damping of soils for shear strains ranging from 10−5 % to 0.5 %. For most soils, the test is non-destructive, and tests may be performed on the same specimen at multiple confining stresses simulating in situ conditions from near surface to great depths. This paper makes use of the transfer function approach for resonant column theory to obtain simple solutions for the test and applies it for two types of resonant column apparatus: the conventional fixed-base free top (including spring top) now referred to as device type 1, and for a new type of resonant column device, device type 2, where a torque transducer is mounted in the bottom platen of the device. Device type 2 uses the torque measured at the base of the specimen and the rotation measured at the top of the specimen to determine the shear modulus and damping. The advantage for taking torque measurements at the base of the specimen is because the torque that is measured is that transmitted by the specimen alone. Calibrations of top platen inertia, stiffness, damping, and torque input are not needed for device type 2. Solution of these equations with complex variables can be done with any number of programming languages. For example, simple, single page, Excel spreadsheets for each device type are provided. The paper concludes with a discussion of issues that need to be addressed before procedures involving non-resonant frequencies can be introduced into ASTM D4015 [ASTM D4015: Standard Test Method for Modulus and Damping of Soils by Fixed-Base Resonant-Column Method, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2007].

Comparison of the Pore Volume in Concrete as Determined Using ASTM C642 and Vacuum Saturation

For the prediction of concrete performance, it is often beneficial to know the volume of pores in the concrete. ASTM C642-13 [Standard Test Method for Density, Absorption, and Voids in Hardened Concrete, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA] was originally introduced in 1969 as a “standard test method for density, absorption and voids in hardened concrete.” This technical note will compare the total pore volume (voids) obtained using ASTM C642-13 with that obtained using vacuum saturation for a typical bridge deck concrete. This technical note suggests that ASTM C642-13 may provide a consistent measure of the pores (voids) in the paste matrix of the concrete; however, it does not provide a measure of the total porosity that may be expected if all the pores in concrete are filled with water. Although an approach like ASTM C642-13 may be sufficient for some applications, the fact that it does not measure the total porosity should be considered by users of the test. This is important because this test method is being frequently applied to concrete durability and transport-related problems that require the total pore volume to be known.

Fracture Toughness Evaluation of Zr-2.5Nb Pressure Tubes Manufactured Employing Double Forging for PHWR700

The need for improvement of the in-reactor performance of Zr-2.5 % Nb pressure tubes arose because of the higher than expected diametral creep rates and variability in axial elongation observed in some of the pressure tubes of 220 MWe Indian pressurized heavy water reactors (IPHWR220). A systematic study revealed that the pressure tubes used in various IPHWR220 had variations in microstructure, mechanical properties, texture, and chemical composition. The forthcoming PHWR700 is expected to operate at a higher temperature than that of IPHWR220 pressure tubes coupled with ∼3 % partial boiling toward the outlet end. The IPHWR220 pressure tubes were manufactured by NFC (Hyderabad, India) using the combination of extrusion-double pilgering with intermediate annealing and with 20 % final cold work. PHWR700 pressure tubes have been manufactured using a combination of forging-extrusion-single pilgering routes. The fracture behavior of cold-worked and stress-relieved Zr-2.5Nb pressure tube material manufactured employing a forging route for PHWR700 is described in this work as a function of hydrogen content (4 and 60 wppm), temperature (25°C–300°C), and sample location. Fracture toughness tests were carried out as per ASTM E1820-06 [ASTM E1820-06: Standard Test Method for Measurement of Fracture Toughness—Designation, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA] using curved compact tension specimens of 17 mm width. The crack growth was along the axial direction of the tube and was measured using the direct current potential drop (DCPD) technique. The fracture toughness of as-received samples show weak dependency on test temperature, whereas samples having 50 ppm hydrogen show typical S curve behavior and regain toughness above 150°C. The variation in fracture toughness across tube length was within scatter band.

Experimental Evaluation of the Pore-Access Size Distribution of Sands

A simple experimental method is presented for evaluation of the pore-access size distribution of sands and, more generally, of cohesionless granular materials. The water-retention curve of a sand specimen is evaluated using a technique similar to the hanging column method (ASTM 2008) [ASTM D6836: Standard Test Methods for Determination of the Soil Water Chararcteristic Curve for Desorption Using a Hanging Column, Pressure Extractor, Chilled Mirror Hygrometer, and/or Centrifuge, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2008] by application of a step-by-step variation of suction and measure of the corresponding changes in water content. The pore-access size distribution is then evaluated from the water-retention curve using the Young-Laplace law, which links the suction to the pore-access radius. The efficiency of this experimental method is demonstrated by studying the influence of various parameters such as the shape and the size of the grains, the spreading of the grain-size distribution, and also the relative density of the specimen on the pore-size distribution.

Sorptivity Ratio and Compressive Strength of Alkali-Activated Blast Furnace Slag Paste

Abstract The initial/secondary absorption and compressive strength of alkali-activated slag (AAS) paste has been investigated. Emphasis has been given to secondary absorption of AAS paste based on the method described in ASTM C1585-04 [Standard Test Method for Measurement of Rate of Absorption of Water by Hydraulic Cement Concretes, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2004, pp. 1–4]. The paste was produced by activating blast furnace slag with sodium hydroxide/potassium hydroxide and sodium silicate solution. The major parameters studied were alkali content, silicate content, and the type of activator. Experimental investigation revealed that initial rate of absorption (Si) and secondary rate of absorption (Ss) decreases with increase in alkali and silicate content up to a certain limit with an increase in compressive strength. The maximum compressive strength was found to be 50.40 MPa for the specimens having lowest sorptivity. It was also found that the sorptivity ratio (Si/Ss) plays a significant role on compressive strength in turn on the durability of AAS composites. This paper is an attempt to introduce the simple method of measuring initial and secondary sorptivity described in ASTM C1585-04 to study the strength and durability of AAS. The microstructure study was carried out using SEM/EDAX.

Investigation of Factors Affecting PCC Surface Resistivity through Ruggedness Testing

Many entities currently use permeability specifications in Portland cement concrete (PCC) pavements and structures. Recent studies have shown surface resistivity testing correlates well with ASTM C1202 [“Standard Test Method for Electrical Indication of Concrete’s Ability to resist Chloride Ion Penetration,” Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2010] rapid chloride penetration (RCP) testing. The success of this research has led to surface resistivity testing on Portland cement concrete cylinders being implemented in Louisiana. However, many of the studies have questioned the impact of various factors on surface resistivity measurements. This project investigates a ruggedness factorial using many of the factors in question to determine the level of impact of each factor. A partial factorial consisting of 35 combinations of factors was developed using 11 factors and 16 mixtures. Some factors were mixture dependent; therefore, RCP testing was also performed on a portion of the factorial to determine if factors influence the surface resistivity meter or permeability in general. The ruggedness study showed age and aggregate type as significant factors for surface resistivity. Additional comparisons against a control suggested age, calcium nitrite, aggregate size, and aggregate type as significant factors for surface resistivity. However, comparative RCP testing on the same sample sets concluded that all significant factors determined either affect the permeability of the sample in general or will influence rapid chloride permeability as well.

A Method to Obtain Straight Crack Fronts During Pre-Cracking of Compact Tension Specimens

Abstract A common problem during pre-cracking of compact tension (CT) specimens is skewed crack fronts. It is also one of the most common reasons for which tests according to, for instance, ASTM E1820-11: Standard Test Method for Measurement of Fracture Toughness, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2012, do not give valid results. This problem is normally a result of the fact that specimens and fixtures are not perfectly aligned, even when the testing setup meets the requirements of ASTM standards. In the present investigation, aluminum bushings have been used to rearrange the loads transferred from the testing machine to the specimens. Geometrical errors were deliberately introduced to the testing setup so that the specimens were asymmetrically loaded. The introduced errors were, however, within the tolerances of ASTM standards. Steel specimens with two different notch types, Chevron and straight notches, were tested, both with and without aluminum bushings. The specimens were pre-fatigued and thereafter broken under monotonic loading. The specimen crack lengths were measured and validated according to ASTM E1820-11. The results related to pre-fatigued specimens with aluminum bushings were shown to be valid, whereas the results for specimens without bushings did not meet the ASTM standards requirements.

Refining Conditions of Fatigue Testing of Hot Mix Asphalt

The beam fatigue test of hot-mix asphalt (HMA) has been used for nearly a half century. However, several conflicting results have been recently reported. This study attempts to refine test conditions such as waveform type (haversine versus sinusoidal), incorporating rest periods between loading cycles, and the effect of rest period on the healing of the HMA to minimize (eliminate) gross errors in the data analysis of the fatigue test results. In the deflection-controlled haversine test [ASTM D7460, 2010, “Standard Test Method for Determining Fatigue Failure of Compacted Asphalt Concrete Subjected to Repeated Flexural Bending,” Annual Book of ASTM Standards, Vol. 04.03, ASTM International, West Conshohocken, PA, pp. 1–14] permanent deformations lead to a new equilibrium neutral position of the beam and the force output follows a sinusoidal waveform. This tends to bend the beam in both directions similar to the deflection-controlled sinusoidal test. This would produce erroneous fatigue results since the test assumptions do not match the actual test conditions. In contrast, the deflection-controlled sinusoidal test [AASHTO T-321, 2012, “Standard Method of Test for Determining the Fatigue Life of Compacted Hot Mix Asphalt (HMA) Subjected to Repeated Flexural Bending,” Annual Book of AASHTO Standards, Vol. 32, Washington, DC, pp. T321-1–T321-11] is more consistent than the deflection-controlled haversine test [ASTM D7460, 2010, “Standard Test Method for Determining Fatigue Failure of Compacted Asphalt Concrete Subjected to Repeated Flexural Bending,” Annual Book of ASTM Standards, Vol. 04.03, ASTM International, West Conshohocken, PA, pp. 1–14]. When tests, with and without rest periods, are compared for healing studies, it is even more important to use a deflection-controlled sinusoidal test in order to obtain a fair comparison and accurate healing results. Since neither the haversine waveform nor the sinusoidal waveform in the lab exactly simulates field conditions, it is important to use a sinusoidal waveform in order to obtain consistent results. It is recommended that ASTM changes the ASTM D-7460 designation and test procedure to require a deflection-controlled sinusoidal waveform instead of haversine. Implementing the recommended test conditions is a crucial step in studying the concept of HMA healing and; as a result, estimating the endurance limit which plays an important role in designing sustainable pavements.

TDR Method for Compaction Quality Control: Multi Evaluation and Sources of Error

Abstract The use of the time domain reflectometry (TDR) method, designated ASTM D6780 (ASTM D6780, 2005, “Standard Test Method for Water Content and Density of Soil in Place by Time Domain Reflectometry (TDR),” Annual Book of ASTM Standards, Vol. 04.09 ASTM International, West Conshohocken, PA), to measure water content and soil density is relatively new with both successful and unsatisfactory results being reported. This paper reexamines the TDR method from various aspects, including laboratory investigation of the relation between TDR-measured electrical properties and soil phase parameters, full scale laboratory evaluation of the standardized methods, real world performance evaluation at construction sites of earth dams, and theoretical reexamination. Laboratory calibration reveals the effect of soil type on soil electrical properties, and its implication on the TDR method is discussed. The full scale laboratory evaluation supports the validity of both the one-step and two-step TDR methods. But the field evaluation at construction sites of earth dams indicates otherwise, particularly in the measurement of soil density. The errors in the two-step method are attributed to the penetration disturbance of the field multipole resonance probe (MRP). An additional source of error in the One-Step method is found to be a theoretical flaw in the current empirical adjustment process for correcting the variation of pore-fluid conductivity from the calibration test to field measurements. Remediation for the two-step method and updating of the ASTM D6780 to overcome the shortcomings of the one-step testing are in progress.

Experiences with ASTM D02 Practices D4378 and D6224 for Turbine Oils and Auxiliary Power Plant Equipment Condition Monitoring Programs

Abstract Condition monitoring practices ASTM D4378 [2011, “Section Five, Petroleum Products, Lubricants, and Fossil Fuels,” Annual Book of ASTM Standards, Vol. 05.02, ASTM International, West Conshohocken, PA] and ASTM D6224 [2009, “Standard Practice for In-Service Monitoring of Lubricating Oil for Auxiliary Power Plant Equipment,” Annual Book of ASTM Standards, Vol. 05.02, ASTM International, West Conshohocken, PA] are important activities at the SC C00 as they are the benchmark today in the power generation industry for condition monitoring and maintenance practices. With the need for increased equipment and plant efficiency in the modern economy, these methods contribute to an improved reliability and better utilization of modern turbine lubricants. In conjunction with the latest ASTM D4303 [Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA] (the new turbine oil specification) these methods help the end-users to better understand the condition of their in-service lubricants and by turning them into immediate maintenance actions. This paper will include a few case studies, presenting the different experiences with the integration of these in-service practices, and how they are evolving with the original equipment manufacturers’ equipment developments and turbine lube oil developments.

Comparison of ASTM C311 Strength Activity Index Testing versus Testing Based on Constant Volumetric Proportions

Abstract Currently, the (pozzolanic) strength activity indices of fly ashes and natural pozzolans are typically evaluated using the procedures outlined in ASTM C311 [“Standard Test Methods for Sampling and Testing Fly Ash or Natural Pozzolans for Use in Portland-Cement Concrete,” Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2007]. In this test, the 7 and 28 d compressive strengths of mortar cubes with a 20 % mass replacement of cement by pozzolan are compared to those of a control without pozzolan, at constant flow conditions. In its current form, this procedure confounds two other properties of the pozzolan with its strength activity, namely its density and its water-reducing/increasing capabilities. In this study, the current C311 testing procedure is evaluated against an alternative in which the 20 % fly ash replacement for cement is performed on a volumetric basis and the volume fractions of water and sand are held constant, which should provide a true evaluation of the strength activity index of the pozzolan, free of these confounding influences. Class C and Class F fly ashes, a natural pozzolan, and a sugar cane ash are evaluated using both approaches, with some significant differences being noted. For a subset of the materials, the strength measurements are complemented by measurements of isothermal calorimetry on the mortars to an age of 7 d. For the constant volumetric proportions approach, a good correlation is exhibited between the cumulative heat release of the mortar at 7 d and the measured 7 d strength, suggesting the potential to evaluate 7 d pozzolanic activity via calorimetric measurements on much smaller specimens.

Correlating Accelerated Laboratory, Field, and Thermal Aging TPO Membranes

Abstract Thermoplastic polyolefin (TPO) roofing membranes have been used in the US low-slope roofing industry as single-ply membranes for over 15 years, and have seen widespread acceptance. TPO membranes have been defined by ASTM Standard D6878-08, “Standard Specification for Thermoplastic Polyolefin Based Sheet Roofing,” Annual Book of ASTM Standards, Vol. 04.04, ASTM International, West Conshohocken, PA, 2008, www.astm.org, which sets a minimum threshold for accelerated weathering performance. To be ASTM D6878 compliant, a TPO membrane shall not show any visual micro-cracking under 7X magnification after being exposed in a xenon arc light apparatus to a minimum irradiance of 10 080 kJ/m2 at 340 nm. While the ongoing development of TPO membranes uses D6878 as the basic standard, it is necessary for individual membrane manufacturers to develop an advanced understanding of TPO long-term weathering durability to further improve confidence in the expected service life. In this paper, a novel ultra accelerated outdoor weathering technique, atlas ultra accelerated weathering system (UAWS), is used to predict long-term weathering durability performance of TPO. The comparison and correlation of this novel technique with other artificial accelerated weathering methods, such as xenon arc light [ASTM G155-05a, “Standard Practice for Operating Xenon Arc Light Apparatus for Exposure of Non-Metallic Materials,” Annual Book of ASTM Standards, Vol.14.04, ASTM International, West Conshohocken, PA, 2005, www.astm.org] and fluorescent UV light [ASTM G154-06, “Standard Practice for Operating Fluorescent Light Apparatus for UV Exposure of Nonmetallic Materials,” Annual Book of ASTM Standards, Vol. 14.04, ASTM International, West Conshohocken, PA, 2006, www.astm.org] are shown and reviewed. The surface temperatures of TPO membranes exposed in the UAWS device as well as in the field are shown to further understand the heat impact on TPO durability. In addition, accelerated heat aging at temperatures up to 138 °C are shown to give very good correlation to other aging tests.

Measurement Uncertainty and Statistical Process Control for the Steiner Tunnel (UL 723, ASTM E84)

In the United States, the Steiner Tunnel (UL 723 [2008, “Test for Surface Burning Characteristics of Building Materials,” Ninth Edition, Underwriters Laboratories Inc., Northbrook, IL], ASTM E84-10 [2010, “Standard Test Method for Surface Burning Characteristics of Building Materials,” Annual Book of ASTM Standards, Vol. 4.07, ASTM International, West Conshohocken, PA.]) is an important fire test apparatus used by the building codes to assess the flammability and smoke generation characteristics of building products (e.g., insulation, sheathing materials, foamed plastics, wood-based products). This paper examines how various tools and methodologies can be used to quantify, improve, and control measurement uncertainty in fire tests, such as the ASTM E84 tunnel test. This paper also assesses uncertainty in the Steiner Tunnel using both a Gage Repeatability and Reproducibility (Gage rR (ii) the development of process control charts to monitor Steiner Tunnel performance; and (iii) a reduced need for calibration and re-verification of Steiner Tunnel performance. The Gage r&R results show that the major contributor to uncertainty in flame spread and smoke developed results is primarily due to the performance difference in the test samples, and not due to the measurement device or the person conducting the test. The uncertainty, in the form of the standard deviation, is also shown in the results of each of the materials tested in the study. Monthly data for the historical reference material, red oak, and a proposed reference material, heptane, are shown to demonstrate stability of the measurement system over time. The heptane test is presented to help measure and reduce uncertainty of the smoke measurement in the Steiner Tunnel.

Loading Rate Effect on the Master Curve Reference Temperature, T, for the A533 B Material

Abstract The National Institute for Nuclear Research in Mexico participated in the international research project “Master Curve Approach to Monitor the Fracture Toughness of Reactor Pressure Vessel in Nuclear Power Plants” coordinated by the International Atomic Energy Agency (IAEA), where the loading rate effect on the Master Curve reference temperature, T0, was investigated. The experimental program consisted in quasi-static and dynamic fracture toughness testing of precracked Charpy specimens on the IAEA reference reactor pressure vessel steel Japanese reference quality (JRQ) (A533 Grade B Class 1), which was analyzed with the Master Curve methodology. The tests were carried out in displacement control at two temperatures, −70 and −60°C, and at three load rates, dK/dt=0.1, 1, and 10 MPa√m/s. The determined reference temperatures, T0 (0.1 MPa√m/s)=−73.6±6.4°C, T0 (1 MPa√m/s)=−63.3±5.4°C, and T0 (10 MPa√m/s)=−50.3±5°C, are similar to those obtained by other laboratories [IAEA Second Meeting on Master Curve to Monitor the Fracture Toughness of RPVs in NPPs, November 2006, Dresden, Germany]. The shift in T0 within the quasi-static loading rate interval (0.1–2 MPa√m/s) recommended by ASTM E1921-05 [“Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transistion Range,” Annual Book of ASTM Standards, Vol. 03.01, ASTM International, West Conshohocken, PA.] is 14.4°C and the shift in T0 between decades of dK/dt on logarithmic scale is 11°C. The empirical relation proposed by Wallin [“Effect of Strain Rate on the Fracture Toughness Reference Temperature T0 for Ferritic Steels,” Recent Advances in Fracture, R. K. Mahidhara et al., Eds., The Minerals, Metals and Materials Society, 1997, pp. 171–182] predicts very well the shift in T0 in the quasi-static loading regime (0.1–2 MPa√m/s). This work provides experimental support to limit the quasi-static loading rate interval in ASTM E1921.

Evaluation of Two Automated Methods for Air-Void Analysis of Hardened Concrete

Abstract Air-void analysis of hardened concrete is typically performed according to ASTM C457–09 [“Standard Test Method for Microscopical Determination of Parameters of Air-Void System in Hardened Concrete,“ Annual Book of ASTM Standards, Vol. 4.2, ASTM International, West Conshohocken, PA], which can be tedious to perform and is operator subjective. Several alternative automated methods have been proposed, two of which are the Rapid Air 457 and the scanner method developed at Michigan Technological University. In each of these methods, images are collected from contrast enhanced surfaces of polished concrete, and image analysis is performed to calculate air-void system parameters. In this research, 22 concrete samples were examined using these two methods, the air-void system parameters were compared to those obtained from the ASTM C457 standard, and the precision of the results was compared to the recommendations of ASTM standard. It was concluded that the total air content and the spacing factor of the air voids measured by Rapid Air 457 and the scanner method were comparable to the air content and the spacing factor measured according to the standard manual method. Considering the fact that the automated image systems could detect air voids smaller in diameter than those typically seen by an operator, it was found that if these small air voids are counted, calculated spacing factors are smaller than those calculated by the manual method. If small diameter air voids are removed from the analysis, then spacing factors agree fairly well with those calculated by ASTM C457 from stereo-optical microscopy.