bluuebunny/crossref_metadata_2025 huggingface dataset:
An Inter- and Intra-Agency Survey of the Use of Plants for Toxicity Assessment
Authors: Smith BM
Published: March 2009

The purpose of this project was to perform an inter- and intraagency survey of the use of plants as test systems for ecological risk assessment and remediation for the United States Environmental Protection Agency Office of Research Development (USEPA/ORD). Four broad classes of plant applications were identified: (1) bioassays; (2) bioindicators; (3) bioremediation; and (4) biotechnology. Improvement to research methodologies would include: (1) developing fluorescence bioassays for terrestrial and aquatic plants and algae and combining plant and animal tests to form regionally differentiated suites of bioassays; (2) development of “natural community” databases and small-scale maps for evaluation of changes in plant community structure to determine the “biotic integrity” of specific habitat types; (3) expand work to develop plants and fungi as biologic remediative tools; and (4) development of guidelines for field trials and eventual full-scale agricultural use of pesticide-producing genetically engineered plants (GEPs).
An Overview of Experimental Design
Authors: Ritter M
Published: March 2009

In experiments that examine the effects of chemicals on plant behavior, good design can overcome the difficulties imposed by limited resources. An appropriate design is one that obtains information about the interactions between and among factors, as well as the curvature, if any, in factor behavior. This paper outlines the chief concepts inherent in effective experimental design: purpose, objective, hypothesis, statistical power, treatment level determination, response variables, design structure, and replication.
Track-Sprayer and Glasshouse Techniques for Terrestrial Plant Bioassays with Pesticides
Authors: Brown RA , Farmer D
Published: March 2009

In order to determine the potential of pesticides to cause damage to nontarget terrestrial plants, assessments of the intrinsic toxicity of the pesticide must be matched to estimates or measures of exposure. This paper describes a glasshouse bioassay which has been developed in order to assess pre- and postemergence toxicity of pesticides to a taxonomic range of crop and weed species. Different techniques used to assess pesticide effects in these tests are compared, and their contribution to the overall toxicological hazard assessment is shown. Use of the glasshouse bioassay to compare (a) effects of a given herbicide on different plant species, (b) effects of different herbicides on one plant species, and (c) differences in pre- and postemergence effects for a given herbicide are demonstrated. Interpretation of the ecological risks in the field based on the glasshouse toxicity data is discussed.
Responses of Spruce Trees (Picea Abies. L. KARST) to Fumigation with Halone 1211—First Results of a Pilot Study
Authors: Schröder P , Debus R
Published: March 2009

Fumigation experiments with young cloned spruce trees were performed in a pilot study to test the trees' ability to react to pollutant impact. After 41 days of exposure to 10-ppb Halone 1211 (difluoro-chloro-bromo-methane), changes in needle fresh weight, protein content, and pigment pattern were observed compared to a control fumigation with purified air. These changes, however, seemed nonspecific reactions to a pollutant climate because they were also obtained after fumigation with nitrogen dioxide (NO2). Only in the halone-fumigated trees was up to fourfold increases of the activity of glutathione-S-transferase, a constitutive detoxification enzyme in spruce observed. The significance of this reaction for biomonitoring of halogenated compounds is discussed.
The Biochemical Basis of the Activation of Promutagens by Plant Cell Systems
Authors: Plewa MJ
Published: March 2009

Plant activation is the process by which promutagenic agents are activated into mutagens by plant systems. Many promutagens are activated by plants as well as by the familiar mammalian microsomal monooxygenase systems. However, several environmentally important agents are preferentially activated by plant cells. Plants have become a reservoir for the deposition and accumulation of environmental xenobiotics. With the widespread use of agricultural chemicals on crop plants and with the global exposure of plants to pollutants, the possibility that plant-activated agents may be introduced into the human food chain is a cause of concern. Environmentally relevant agents should be evaluated with plant assays. The plant cell/microbe coincubation assay uses cultured plant cell suspensions as the activating system and bacteria or yeast cells as the genetic indicator organism. After a treatment time, the microbes are plated on selective medium. In this way the activation system and the genetic system can be independently studied. In addition, the viability of the plant cells and the microbial cells can be independently determined so that the toxicity of a test agent can be evaluated. We have employed cultured tobacco, cotton, carrot, maize, and Tradescantia cells to study the activation of test agents and complex environmental mixtures. In addition to screening, this assay is being used in basic research to elucidate the biochemical mechanisms of plant activation. The results of experiments using the peroxidase inhibitors acetaminophen and diethyldithiocarbamate showing repression of TX1-cell activation of m-phenylenediamine and 2-aminofluorene indicate that a TX1-cell peroxidase pathway is involved in the plant activation of aromatic amines.
Activation of Aflatoxin B1 and Benzo(a)pyrene by Tobacco Cells in the Plant Cell/Microbe Coincubation Assay
Authors: Gentile JM , Johnson P , Robbins S
Published: March 2009

We investigated the ability of tobacco (TX1) cells in culture to activate aflatoxin B1 (AFB1) and benzo(a)pyrene (BAP) using the plant cell/microbe coincubation assay. Initial experiments with Salmonella typhimurium as a genetic endpoint using previously published assay conditions failed to demonstrate that either of these agents could be activated into a mutagenic form by TX1 cells. However, when modifications of the assay, including increased plant cell densities and/or increased preincubation times, were employed, both AFB1 and BAP were demonstrated to be potent plant promutagens. These data demonstrate that, for the purpose of routine screening and toxicity assessment studies focusing upon plant activation, careful attention must be paid to both the chemical or complex mixture under study as well as to the metabolic potential of the particular plant cell system employed. This will ensure a more complete understanding of the problem at hand, provide insight into the mechanisms of activation, and guard against possible false negative results.
A Method for On-Site Evaluation of Phytotoxicity at Hazardous Waste Sites
Authors: Nwosu JU , Ratsch HC , Kapustka LA
Published: March 2009

On-site methods using the seed germination test to evaluate the phytotoxicity of hazardous waste site soils are advantageous because samples are not removed from the site and time is saved in soil handling and preparation. Seedlings may be collected at the end of the test and taken to the laboratory for further analyses. We have used the Magenta™ GA-7 test vessels to conduct on-site the germination of cucumber, Cucumis sativus L. var. Hybrid Calypso, and wheat, Triticum aestivum L. var. Stephens. Site soil was sampled using a premeasured cup that held a volume nominally equivalent to 100 g of soil. Twenty pregraded seeds were planted in the soil in each test container and covered with 16-mesh silica sand. Site soil was irrigated with water to approximately 45% moisture on a dry weight basis, covered, and left under a shade at the test site for five days. After five days, germinated seeds were counted and percent germination values were calculated for each seed species. Controls for the test were performed on-site, using 16 and 20-mesh silica sand. Test performance was evaluated against the companion laboratory seed germination test. Calculated percent germination values in the cucumber seeds indicated statistically significant (α = 0.05) but biologically reasonable differences between the laboratory test and the field test. Cucumber seeds showed a greater difference, while the wheat seeds did not show any significant difference between the tests.
Use of Marsh Plants for Toxicity Testing of Water and Sediment
Authors: Walsh GE , Weber DE , Simon TL , Brashers LK , Moore JC
Published: March 2009

The freshwater wetland plants, Echinochloa crusgalli crusgalli and Echinochloa crusgalli zelayensis, and the saltmarsh plant Spartina alterniflora were exposed to the herbicides metolachlor and norflurazon in two types of toxicity tests: (1) seed germination and early seedling growth in water, and (2) seedling survival and growth in natural and synthetic sediments. The synthetic sediments were formulated to be similar to the natural sediments with regard to particle size distribution and organic content. The herbicides did not affect rate of germination, but significantly inhibited rate of early growth and survival and rate of growth of older seedlings in sediments. Echinochloa was more sensitive than Spartina to both herbicides. Inhibition of the growth rates of the two varieties of E. crusgalli was similar in natural and synthetic sediments, but inhibition of growth of S. alterniflora was greater in synthetic than in natural sediment. It is concluded that the species tested may be used for estimation of potential effects of toxicants on wetland plants and that synthetic sediments of known composition may be used in sediment toxicity tests.
A New Plant Life-Cycle Bioassay for Assessment of the Effects of Toxic Chemicals Using Rapid Cycling Brassica
Authors: Shimabuku RA , Ratsch HC , Wise CM , Nwosu JU , Kapustka LA
Published: March 2009

Initial evaluation of a new plant life-cycle bioassay for the assessment of the effects of toxic chemicals is presented. The bioassay features a rapid cycling Brassica species that can complete its life cycle in as little as 36 days. The herbicide dalapon (2,2-dichloropropionic acid) was used as the test substance to develop the bioassay. Plants were exposed to nine levels of dalapon solution in a 0.5x geometric series ranging from 0 to 200 ppm (mg/L) in separate postemergence and preemergence application experiments. Harvest biomass was generally reduced by concentrations as low as 12.5 ppm. Similarly, foliar height was reduced at concentrations as low as 25 ppm. Stem diameter was reduced at concentrations above 50 ppm. Although fertile silique counts were quite variable, no siliques were formed at dosages greater than 12.5 and 50 ppm for postemergence and preemergence treatments, respectively. Mortality occurred only with the 200-ppm preemergence treatment. The higher sensitivity of the reproductive stage is of significance to the ecological success of the plant population and demonstrates the value of life-cycle bioassays.
Use of Plants for Toxicity Assessment of Heavy Metal Rich Industrial Effluents
Authors: Somashekar RK , Siddaramaiah
Published: March 2009

The objective of this study was to evaluate phytotoxicity tests for screening and biomonitoring complex effluent samples. Seed germination tests were conducted using three effluent samples from three industrial sources. Five types of seeds were tested. Complete inhibition of germination was, however, not observed in any case. Zea mays and Dolichos biflorus were the most sensitive. There occurred a significant difference in root/shoot length and dry weight between treated and control samples at P < 0.01 and P <0.05. Results of definitive tests indicated a linear concentration-effect relation. The study indicated that phytotoxicity tests involving higher plants have a high potential for use in the biomonitoring of industrial effluents because of simplicity and sensitivity. It is concluded that the test employed here could be suitably adopted with slight modifications for tropical conditions.
Cyanophage/Host Assay for Toxicity Assessment in Water, Wastewater, Sludges, and Composts
Authors: Kraus MP
Published: March 2009

It has been demonstrated that cyanobacterial viruses (cyanophages) arise in sewage treatment and are present in streams receiving treated sewage. While algae alone are often proposed for toxicity assessment, the method presented here uses the cyanophage/host interaction, thus bringing the assay into the realm of molecular biology. Examples of its application to water, sewage, and sludge treatment, to high nitrate, to herbicides and viricides, and to composts support its value for initial screening or first-tier toxicity assay. Its ability to deal with principles and mechanisms at the molecular level and to incorporate progress in DNA and protein methodologies adds to its significance and utility at higher levels of toxicity assessment.
Materials Evaluation Using Wet-Dry Mixed Salt-Spray Tests
Authors: Lyon SB , Thompson GE , Johnson JB
Published: March 2009

Accelerated methods for corrosion testing of materials, based on the use of salt sprays, have been standardized since the early 1930s. However, despite the many significant advances in the mechanistic understanding of atmospheric corrosion phenomena since those days, most changes in accelerated test standards have been implemented to reduce the time of the tests, and thus their costs, by increasing their severity. Thus, although laboratory accelerated test methods have played an important role in the assessment of materials' performance, in general they have not been applied by virtue of their ability to simulate and enhance natural weathering. In particular, wet-dry cycles simulate the natural wetting and drying which occurs in practice and, under many conditions, can aid in the formation of naturally occurring corrosion product films, which frequently play a role in the kinetics of metal corrosion. In addition, the use of a relatively dilute mixed salt spray, in comparison with the more commonly used solutions based on 5% NaCl (e.g., ASTM B 117, Method for Salt-Spray Fog Testing) can result in corrosion morphologies and behavior which are more representative of natural conditions. This paper describes a wet-dry mixed salt-spray test using solutions containing mixtures of (NH4)2SO4 and NaCl with a 1-h wet/1-h dry cycle. The basis and reasons for using the test are discussed in depth with the emphasis on illustrating the improvements in realism which are attained using this procedure rather than a standard continuous NaCl test. In addition, the results from accelerated corrosion testing of aluminum are presented to illustrate the main features of the test. Finally, possible developments and improvements in the salt-spray methods, including the use of solutions resembling artificial rainwater, are discussed.
Accelerated Test for Determining Microbiological-Influenced Corrosion Resistance of Aluminum Alloys
Authors: Rosales BM , Ayllon ES , Leiro MC
Published: March 2009

This paper summarizes the experience developed during various research work performed using 2024-T3, 7075-T6, and 7005-T6 aeronautical aluminum alloys in different natural and laboratory aqueous media.

The effect on corrosion of the components of a mineral aqueous nutrient medium that supports fungus proliferation was evaluated using an electrochemical technique. Through anodic and cathodic potentiokinetic polarizations, it was possible to determine the susceptibility, type, and relative amount of corrosion damage to the alloys in the medium as well as changes in the medium caused by the metabolic consumption of its components.

The microbiological-influenced corrosion (MIC) effects associated with metallurgical characteristics of the alloys, such as the thermomechanical treatments, secondary phases, and surface roughness, were also determined by means of the polarization tests. These tests are very useful accelerated techniques to evaluate the susceptibility of an aluminum alloy to localized attack in a given environment. They also provide information concerning the morphology and magnitude of the damage.
Corrosion of Aluminum and Aluminum Alloys in Nitric Acid
Authors: Horn E-M , Diekmann HW
Published: March 2009

Corrosion tests in nitric acid were made using a freshly vacuum-distilled (18°C, 55 mbar) nitric acid diluted to concentrations of 10 to 99.8%, with varying nitrogen tetraoxide (N2O4) contents. The duration of testing in the various nitric acid concentrations was from 6 days up to 1 year. The corrosion rates were determined by atomic absorption (AAS), using the percentage of aluminum (and alloying elements) dissolved in the nitric acid. Several wrought aluminum materials—such as A199.99 (3 ppm copper), A199.5 of three different strength levels, Al-Mg1, Al-Mg2.5, Al-Mg-Si0.5, Al-Mg-Si1, Al-Mn, Al-Mn1-Mg0.5, Al-Mg2-Mn0.8, Al-Mg2.7-Mn, G-A199.99, G-A199.8, G-A199.5, G-Al-Mg2.7-Mn, and G-Al-Mn—were used in the investigation. The alloys Al-Mg1, Al-Mg-Si1, Al-Mg2-Mn0.8, Al-Mg-Si0.5, and Al-Mn1-Mg0.2 showed corrosion rates comparable to those of the aluminum grades. Cast aluminum samples were taken from sections of continuously cast bar of the following materials: G-A199.5, G-A199.8, G-A199.99, G-Al-Mn, G-Al-Mg2.7-Mn, and G-Al-Mg2-Mn0.8. The corrosion rates show the advantage of the purer grades with respect to the weight loss. A marked influence of heat treatment, however, can be observed with samples of aluminum alloys produced by continuous casting. The investigation has clearly demonstrated that pure and high-purity grades of aluminum, as well as several aluminum alloys, are well suited for handling highly concentrated nitric acid.
The Breaking Load Method: Results and Statistical Modification from the ASTM Interlaboratory Test Program
Authors: Colvin EL , Emptage MR
Published: March 2009

The breaking load test provides quantitative stress corrosion cracking data by determining the residual strength of tension specimens that have been exposed to corrosive environments. Eight laboratories have participated in a cooperative test program under the auspices of ASTM Committee G-1 to evaluate the new test method. All eight laboratories were able to distinguish between three tempers of aluminum alloy 7075. The statistical analysis procedures that were used in the test program do not work well in all situations. An alternative procedure using Box-Cox transformations shows a great deal of promise. An ASTM standard method has been drafted which incorporates the Box-Cox procedure.
Detection and Monitoring of Localized Corrosion of Aluminum Alloys with Electrochemical Impedance Spectroscopy
Authors: Mansfeld F , Lin S , Shih H
Published: March 2009

The impedance spectra for aluminum alloys and aluminum-base metal matrix composites have been found to change drastically when localized corrosion occurred during exposure to 0.5N NaCl. Similar results have been obtained for a model pit in aluminum 6061 alloy. These changes include a large increase of the capacitance and the occurrence of a transmission line element. A model for the impedance behavior has been developed which can be used for the analysis of the experimental data. Under certain assumptions it is possible to obtain pits growth rates and their changes with exposure time from measurements of the polarization resistance of the pit Rpit at the corrosion potential. Electrochemical impedance spectroscopy (EIS) has been found to be a very sensitive tool for detecting the initiation and propagation of localized corrosion of aluminum alloys. Examples are given for Al 6061-T6, Al 7075-T6, aluminum/silicon carbide and aluminum/graphite during exposure to NaCl.
Examination of the Influence of Lithium on the Repassivation Rate of Aluminum Alloys
Authors: Stoudt MR , Vasudevan AK , Ricker RE
Published: March 2009

The influence of lithium on the rate of repassivation of aluminum alloys was studied by conducting scratch-repassivation experiments on samples with differing lithium and copper contents and with differing heat treatments in a buffer solution containing either 0.5M sodium sulfate or 0.5M sodium chloride. The experiments were conducted under either open circuit conditions, with the resulting potential transient recorded, or under potentiostatic conditions, with the resulting current transient recorded. Due to the rapid repassivation rate of aluminum alloys, unique experimental and analytical procedures had to be developed. In particular, the experiments were designed to minimize the time between initiation and completion of the scratch and to generate the bare surface at a constant rate. A constant bare surface generation rate allowed for determination of the bare surface current density from the slope of the rise transient rather than from the maximum current observed as done by previous investigators. The bare surface current density determined in this manner was always greater than that calculated from the maximum current. Lithium in solid solution was found to slightly increase the bare surface current density but it did not significantly alter the rate of repassivation over the range of lithium concentrations studied. The precipitation of lithium phases altered the repassivation behavior but, the nature of the observed changes depended on the type of precipitate.
The Development of European Test Methods for the Measurement of Engine Oil Viscosities at Low Temperatures
Authors: Vickars MA , Huby FJ , Jordan CE , Bates TW , Müller HD
Published: March 2009

In response to the Society of Automotive Engineers' (SAE) desire to introduce cold-cranking viscosity limits measured at temperatures specified for each W-grade of engine oil, the Co-ordinating European Council (CEC) joined ASTM in 1982 in determining a precision statement for the so-called “Multi-Temperature CCS Method”. In 1990, CEC again collaborated with ASTM in a similar round-robin test which this time yielded a precision sufficiently encouraging for ASTM to ballot for Standard Test Method status. Two new techniques (differential scanning calorimetry and gas chromatography simulated distillation) differentiated between a limited population of good and poor industry pumpability reference oils. These techniques indicated that some model SAE 10W-30 oils blended from “critical” base oils could be potential pumpability problem oils despite acceptable borderline pumping viscosities in the Brookfield viscometric using the TP-1 cooldown cycle. The DSC and GC techniques are recommended as screening tests when developing new formulations. The development of a low-temperature oil pumpability test method employing the Brookfield viscometer in conjunction with the cooling cycle adopted in ASTM D4684-86 is described. Reference is made to a new, European-designed, high-precision viscometer for the measurement of low-temperature cranking viscosities.
Shear Stresses Imposed on Oils During Low-Temperature Starting
Authors: Alexander DL
Published: March 2009

The shear stresses acting upon engine oils during low-temperature starting are estimated and compared with the shear stresses of several engine oil pumpability tests. The area around the pickup tube and the flow within the pickup tube are considered. The shear stresses in the area surrounding the oil pickup tube are appreciably higher than the yield stress limit of ASTM Standard Test Method for Determination of Yield Stress and Apparent Viscosity of Engine Oils at Low Temperature, (D 4684), and much higher than the shear stress of ASTM Test Method for Low Temperature, Low Shear Rate, Viscosity/Temperature Dependence of Lubricating Oils Using a Temperature Scanning Technique (D 5133). In the flow of oil up the pickup tube, the shear stress is in the same neighborhood as the shear stress of ASTM D 4684.
Low Temperature Pumpability in Gasoline Engines: Establishing Performance at Critical Locations
Authors: Machleder WH , O'Mara JH , Kopko RJ , Stambaugh RL
Published: March 2009

An extensive series of low temperature cold room pumpability studies has been conducted in gasoline engines. Much of the work, although focusing on the role of the Viscosity Index (VI) Improver in SAE 5W-30 and SAE 10W-30 engine oils, has also addressed the issue of measuring oil performance at critical engine locations. In anticipation of an industry-wide re-evaluation of low temperature engine oil pumpability, it is hoped that this work can help the industry refine the Mini-Rotary Viscometer (MRV), and other bench test procedures. A correlation with critical oiling, rather than the generation of oil pressure at the oil sensor light location which is the basis for the pumpability component of the SAE J300 classification, would improve the system. It is clear from this work that the time to generate oil pressure at the oil filter is considerably shorter than the time it takes to generate oil pressure, or oil flow, at critical locations downstream. It is also clear that oil formulation plays a significant role in the low temperature pumpability performance. The engines evaluated in this work were a 2.2 L I-4 OHC, a 2.3 L I-4 OHC and a 3.8 L V-6 push rod engine.
Design and Testing to Reduce Efflorescence Potential in New Brick Masonry Walls
Authors: Chin IR , Petry L
Published: March 2009

Efflorescence is a deposit of substances leached from the masonry either onto the surface or into the pores of brick masonry walls. These deposits may be the substances themselves or secondary reaction products of them with the atmosphere. Investigations of efflorescence on brick masonry walls on dozens of structures throughout the United States by the authors and their colleagues have revealed that the efflorescence on approximately 50 percent of the 43 samples studied consists of water soluble sulfate compounds and that the efflorescence on approximately 40 percent of the samples studied consist of calcium carbonate (carbonated calcium hydroxide) that is not soluble in water. Whenever sulfate compounds are predominant in efflorescence on brick masonry, the source of the efflorescence is usually the brick. Calcium carbonate “efflorescence” originates from the mortar. These data strongly suggest that water soluble efflorescence on brick masonry is most likely a sulfate compound which originated from the brick.

To reduce the potential for efflorescence development in brick masonry walls, the bricks manufactured for a specific building should be tested in accordance with ASTM C 67, Method of Sampling and Testing Brick and Structural Clay Tile. In addition, they should be chemically analyzed for water-soluble constituents to assess the efflorescence potential of the brick.

The potential for efflorescence development in brick masonry walls can also be reduced through the use of drainage type walls with a proper flashing and weep system and through the use of good construction practices and proper material selection.
Brick Veneer Walls - Proposed Details to Address Common Air and Water Penetration Problems
Authors: Piper RS , Kenney RJ
Published: March 2009

Common problems with brick veneer walls include inadequately sealed flashing, poorly draining cavities, excessive air infiltration, and large thermal bridges through the back-up walls. This paper proposes brick veneer wall details that directly address these problems and which provide a durable wall assembly that is expected to retain its weather resistance and thermal properties for the life of the wall. It is proposed that a properly sealed air barrier membrane be applied at the back of the cavity and that glass fiber drainage insulation be installed in the cavity, the full depth of the cavity.
The Influence of Horizontal Reinforcement on the Shear Performance of Concrete Masonry Walls
Authors: Foltz S , Yancey CWC
Published: March 2009

This report documents one experimental investigation which is part of an overall program of research on the properties of concrete masonry. The primary objective of this testing was to evaluate the effect of the quantity and the distribution of horizontal reinforcement on masonry walls under cyclic in-plane loading which fail by a shear mode (primarily diagonal cracking). The ten wall specimens in the current investigation were subjected to an average of over forty loading cycles. Nine to eighteen of these cycles were applied before yield and loss of load capacity. The walls were subjected to cycles of increasing displacements separated by “degradation cycles.”

All ten walls were seven courses high (56 inches or 1.42 m) and three blocks wide (48 inches or 1.22 m) and made from similar concrete block and mortar. The concrete blocks used were hollow block having a unit compressive strength of 1900 psi (13.1 MPa) based on the gross area. The mortar was proportioned as type S. Reinforcement was provided by two types of steel. Rebar steel was placed in grouted bond beams. As an investigation of an alternative method, 9-gage ladder type reinforcement was placed in the bed joint of some walls. Axial load was 39.3 kips (174.9 kN), resulting in a uniformly distributed pressure on the net cross section of 200 psi (1.38 MPa).
Interim Report on a Study to Determine Lap Splice Requirements for Reinforced Masonry
Authors: Schuller MP , Hammons MI , Atkinson RH
Published: March 2009

An investigation of parameters which affect the strength of lap splices within reinforced masonry is currently being conducted as part of the U.S. Army Corps of Engineers program for Construction Productivity Advancement Research (CPAR). Results from the first phase of the investigation complement existing data regarding lap splices in reinforced masonry and provide a comprehensive review of the effects of masonry unit width, masonry unit type, reinforcing bar diameter, and lap length on both the strength and monotonic behavior of lap splices in masonry.

Results of the experimental investigation have shown that the linear relationship used by current working stress masonry design standards does not accurately describe ultimate splice capacity in some cases. An alternate model, adopted for use in the proposed Masonry Limit States Design Standard, provides a more rational approach to the determination of lap splice lengths in masonry. This method considers reinforcing bar diameter and yield strength, grout tensile strength, and masonry wall thickness when determining splice length. Experimental results are in good agreement with values provided by this analysis and have been used to further verify the applicability of the model.
Seismic Behavior of Unreinforced Hollow Clay Tile Infilled Frames
Authors: Flanagan RD , Bennett RM , Beavers JE
Published: March 2009

The U.S. Department of Energy's Y-12 Plant, located in Oak Ridge, Tennessee, is conducting a comprehensive research program to evaluate the seismic capacity of unreinforced hollow clay tile infilled steel frames. This paper summarizes analyses and the results of in-situ and laboratory testing. Evaluations of unit tile, mortar, masonry assemblages, and large-scale building components are presented. Building components tested include infilled frames loaded in-plane and out-of-plane.
A Study of the Compatibility of Brick and Mortar or Maximizing Masonry Bond Strength
Authors: Krauklis AT
Published: March 2009

With the increasing prevalence of steel-stud brick-veneer curtain wall construction, the requirement for reliable bond strength has become critical for sound masonry performance. This paper presents a study, including test data and the result interpretation, used in the selection of a compatible brick and mortar mix for a particular project and a comparison with current design practice. Eight (8) brick types and 24 mortar mixes were examined. Of the 24 mortar mixes, 20 were Type “S.” The study was conducted in three parts. The first part commenced in May of 1987, and the third part continues today, with prisms over 1,600 days old. The results of 110 flexural tests conducted in accordance with ASTM Test Method for Flexural Bond Strength of Masonry (E 518), and over 1,700 bond-wrench tests conducted in accordance with ASTM Method for Measurement of Masonry Flexural Bond Strength (C 1072) are presented. This study reinforces the need for research and compatibility testing in the selection of the masonry components to be used on a project where reliable bond strength is required.
Flexural Bond Strength of Concrete Masonry Prisms Using Masonry Cement Mortars
Authors: Melander JM , Ghosh SK , Dubovoy VS , Hedstrom EG , Klingner RE
Published: March 2009

Results of a test program to determine flexural bond strengths associated with Type M, S, and N portland cement/lime mortars under controlled test conditions were reported in the February 1991 issue of The Masonry Society Journal. Subsequent to that investigation on portland cement/lime mortars, similar tests were performed using masonry cement mortars. In these tests,flexural bond strengths were determined for Type S and Type N masonry cement mortars, using special standard concrete brick. The laboratory tests were designed to control materials, prism fabrication, curing, and testing. The mortar materials included Type S and Type N single-bag masonry cements and standard Ottawa sand. Results of tests conducted at Construction Technology Laboratories, Inc. (CTL), at the research laboratory of the National Concrete Masonry Association (NCMA), and at the University of Texas at Austin (UTA) are summarized and discussed in this paper.

For each of the mortar mixes, the initial flow, water retention, air content, and cube compressive strengths at 7 and 28 days were determined. Six prisms,each consisting of six standard concrete brick and five mortar joints, were fabricated and tested for flexural bond strength at 28 days according to ASTM C 1072-86, Method for Measurement of Masonry Flexural Bond Strength. Tests of some mortars were duplicated in different laboratories. The mean, standard deviation, and coefficient of variation were calculated for the 30 joints tested in each test series. Results provide a general indication of the flexural bond strength of masonry cement mortars under the test conditions of the program.
Influence of Aggregate Microstructure on the Volume Stability of Lightweight Concrete Masonry
Authors: Bremner TW , Rae D
Published: March 2009

The microstructure of four types of manufactured lightweight aggregate was studied using scanning electron microscopy and the results were used to provide insight into the dimensional stability of concretes made from these aggregates. Dimensional stability was determined according to the Test Method for Length Change of Hardened Hydraulic-Cement Mortar and Concrete (ASTM C 157) as modified by the procedures covered in the Specification for Lightweight Aggregates for Concrete Masonry Units (ASTM C 331).

Aggregate types studied were rotary kiln produced expanded shale, sintered fly ash, palletized cold bonded fly ash and expanded glass. Scanning electron microscopy revealed the nature of the aggregate pore structure and the extent to which the vesicular structure, typical of most lightweight aggregates, is interconnected. When used in concrete, the three aggregates produced at high temperature met the ASTM C 331 shrinkage requirements while the one made by cold-bonding did not. After 100 days of drying the aggregates were immersed in a lime saturated water for an additional 251 days, followed by air drying during which length measurements were taken periodically. The microstructure was shown to have a pronounced effect on the volume stability of the aggregate.
Flexural Bond Strength Testing - An Evaluation of the Bond Wrench Testing Procedures
Authors: McGinley WM
Published: March 2009

The recent adoption of flexural tensile bond as a criterion for acceptance of materials in building construction by the Uniform Building Code has directed considerable attention to the ASTM C 1072 - 86 Standard Method for Measurement of Masonry Flexural Bond Strength and the bond wrench testing apparatus. Described is an experimental evaluation of the Bond Wrench Testing Apparatus and testing procedures. During the investigation a device for calibration of the bond wrench was developed and evaluated.
Predicting Durability of Brick Veneerwalls in Cold Climates
Authors: Lovatt JE
Published: March 2009

Bricks in brick veneer walls of modern buildings in cold climates are exposed to frequent cycles of freezing and thawing, and may have high moisture content during these cycles. Poor air barriers, humidified buildings, higher insulation levels, and less emphasis on details to guide rainwater away from brick surfaces all contribute to this severe environment. Freezing while wet is a major contributor to spalling and premature failure of bricks. A model has been developed to provide a quantitative estimate of the time to freezing-induced failure of bricks in a veneer wall, given the local climate, the brick characteristics, and building design and operating conditions.
Evaluation of ASTM E 514-90 Water Penetration and Leakage Test to Assess Performance of Integral Water Repellent Admixtures
Authors: Chin D , Gates RE
Published: March 2009

Integral water repellent admixtures have played an important role in improving performance of architectural concrete block by minimizing penetration of water into the concrete block wall. The ASTM E 514-90 Test Method for Water Penetration and Leakage through Masonry is commonly used to measure the performance of unit masonry subjected to a 4 hour simulated wind-driven rain. A laboratory test program was conducted to evaluate the effectiveness of the ASTM E 514-90 test method in determining performance of walls constructed with materials which contain integral water repellent admixtures, to determine the effect of extending the test period from 4 hours up to 72 hours and to compare the performance of four different integral water repellent admixtures.

Suggestions are made regarding potential modifications that can be made to the E 514-90 test in order to effectively evaluate the performance of walls constructed with concrete masonry units and mortar which contain an integral water repellent admixture.
Including ASTM E 514 Tests in Field Evaluations of Brick Masonry
Authors: Hoigard KR , Kudder RJ , Lies KM
Published: March 2009

Field evaluations of brick masonry are performed for quality control or investigative purposes. One of the many indicators of masonry performance is the permeability of the outer wythe. Field measurements of water permeability can be made using an adaptation of the procedures and equipment of ASTM Standard Test Method for Water Permeance of Masonry (E 514). This paper discusses case studies of field applications of E 514, the techniques used to obtain consistent and valid information, and some concerns about misapplication of the procedure. Modified ASTM E 514 has been found to be a useful field technique for masonry evaluations.
Quantification of Masonry Deterioration Through Statistical Modelling -- A Case Study
Authors: Whitlock AR , Fairley WB , Izenman AJ
Published: March 2009

Structures of all types experience physical damage due to numerous conditions or circumstances. Errors in design, defective materials, improper construction, or poor workmanship can lead to deterioration or failure of building structures or components. Natural aging processes, chemical attack, or the effects of natural disasters create damage. Determining the precise causes or mechanisms responsible for the condition is important and the procedures for doing so have been well researched and published. Also important, however, is quantifying the amount of damage. Quantification is important so that accurate estimates of repair costs can be established, budgeting for the repairs, and for scheduling.

This paper presents a case study concerning a condition survey of five nearly identical buildings constructed of fired clay masonry. Specifically, the surveying and estimation of spalled masonry units is discussed. In this case study, total damage is first assessed by means of two different and independent observational procedures, one of which suffers from incomplete data collection. Missing data are estimated using Poisson log-linear regression modelling of the relationship between damage assessments and a number of qualitative factors. The resulting two sets of predicted total damage estimates are then obtained through calibration techniques.
Evaluation of Injectable Cementitious Grouts for Repair and Retrofit of Masonry
Authors: Atkinson RH , Schuller MP
Published: March 2009

Injection of grout into cracks may be used as a form of repair following a damaging event or as a means to strengthen multi-wythe masonry, enhancing composite action between the wythes. An experimental program has been conducted to evaluate grouting procedures, the suitability of different types of cementitious grouts for injection, and the effect of grout injection on structural behavior.

Over 30 separate mixes utilizing various cementitious components, aggregates, admixtures and different water/cement ratios have been evaluated. A standardized series of evaluation tests have been used to compare injectability, mix stability, and grout properties for each of the mixes. These grouts possess properties similar to the masonry being repaired, and would be available for widespread use as a material for masonry repair. An additional contribution of this research has been the application of nondestructive techniques as a means of measuring quality of the injection process.
Cladding an Existing Building with Masonry Veneer
Authors: Cole GG , Kelley PL
Published: March 2009

Brick is highly regarded as a durable, low-maintenance cladding material. As a result it is often the material of choice for recladding an existing building. Masonry recladding projects are, however, oftentimes problematic. It is challenging to detail and install a masonry veneer, particularly if the building was originally clad with another material. Owners also typically have high expectations for the recladding, especially if the previous cladding failed prematurely. The projects are further complicated if the building is occupied and interior operations must be maintained throughout the construction process. These factors have led to substantial cost and schedule over-runs on several projects. As a result, many owners, designers, and contractors are reluctant to engage in recladding projects. Recladding need not be intimidating. A sound technical approach and a carefully selected and managed project team can successfully undertake and complete a recladding project. With illustrations from a recently completed project, this paper explores the major technical challenges, design constraints, material considerations, and coordination requirements that are encountered in a recladding project.
Failures of Interior Masonry Halls Subjected to Lateral Air Pressure
Authors: Kaskel BS , Romero RC
Published: March 2009

Interior masonry partition walls in three different buildings were found to fail when subjected to significant unanticipated lateral loads due to air pressures. These walls were built around the 1970's and were empirically designed. Governing codes then, as now, commonly required that an interior partition be designed to sustain a lateral load of 5 Ibs. per sq ft (24.4 kg per sq meter). In one case, loads of 15 Ibs. per sq ft (73.2 kg per sq meter) were recorded by instrumentation of the walls.

The investigation and its findings are presented for each of the three case studies. Lessons learned from these examples about lateral loads and the design of masonry partition walls are presented to assist in future designs. This paper also reviews empirical design and minimum design load provisions in current codes and standards to examine whether they accurately account for such load cases.
Urethane Foam Injection as a Method of Remedial Repair for Masonry Cavity Walls
Authors: Kenney RJ , Piper RS
Published: March 2009

In 1981, various tests were performed by the authors to determine if the injection of a urethane foam into the cavity of a typical cavity wall system would substantially alter the properties of the wall system and, more important, if the normal adhesive properties of the polyurethane would bond the veneer outer leaf sufficiently to prevent loosening of the outer leaf during periods of excessive movement. Tests included both laboratory tests on cavity wall panels and samples taken from the wall systems of projects where the cavity walls were repaired using the foam injection method.

Evaluations were made as to the practicality of the repair method and long-term durability of the urethane foam. One building approximately 21 years old, six buildings 5 to 9 years old, and two buildings 1 to 2 years old were monitored to see if the foam material injected into the cavity could have a long-term effect on dimensional stability.

The increased structural capacity of similar cavity wall systems when filled with foam to form a composite structure was substantial. The increase in bond and the bonding of each veneer unit to the substrate was also a benefit of this repair method.

This repair method offers a relatively inexpensive method of remedial repair of cavity wall systems, and can have wider applications particularly in areas prone to earthquake.
Deterioration and Stabilization of Berea Sandstone on the Hamilton County Courthouse
Authors: Herget FA , Crooks RW
Published: March 2009

A rehabilitation program is underway for the 114 year old Hamilton County Courthouse (Indiana). The exterior masonry of the Courthouse is composed of Berea Sandstone and hydraulically pressed face brick. Poor details and workmanship along with improper maintenance have led to the extensive deterioration of the exterior masonry. Much of the sandstone is delaminating in thin layers and falling from the building. This is believed to have been caused by cyclical freezing of the saturated stone. Repair documents have been prepared utilizing proven methods and materials. These repairs are discussed in detail.
New Trenching Method Using Synthetic Bio-Polymers
Authors: Tallard GR
Published: March 2009

For the first time, a radical departure from solidly established concepts and practices based on the use of bentonite for trenching under slurry, is proving itself as a viable alternative. It is even more so in this age of acute environmental sensitivity. The role played by polymers, and in particular a synthetic biodegradable polymer, are taking an increasing role in geotechnical construction: cohesionless sands can be cored with 100% recovery and small and large diameter soft ground tunnels are being bored with greater ease. Of interest to the field of slurry trenched excavations is the new ability to excavate under slurry, be it for continuous deep french drain or for a panelized reinforced concrete diaphragm wall, using a same and totally new kind of slurry. This slurry is a solution of polymers combined with either natural fines or added colloids. Since the slurry is naturally biodegradable, it can be used in all situations. The biodegradation can be deferred by inhibitors and with pH control while regulating it according to needs.

Leachate collection or recharge french drains installed under slurry are presented from the conceptual and QC perspectives. Since most structural slurry wall projects are in urban areas, where working with clay muds is problematic for many reasons, the writer examines the advantages of going from bentonite to polymer slurries. The limitations of the new technology are also discussed.