Alkali Content of Fly Ash – Measuring and Testing Strategies for Compliance, TR-628, 2015

Sodium and potassium are the common alkalis present in fly ash. Excessive amounts of fly ash alkalis can cause efflorescence problems in concrete products and raise concern about the effectiveness of the fly ash to mitigate alkali-silica reaction (ASR). The available alkali test, which is commonly used to measure fly ash alkali, takes approximately 35 days for execution and reporting. Hence, in many instances the fly ash has already been incorporated into concrete before the test results are available. This complicates the job of the fly ash marketing agencies and it leads to disputes with fly ash users who often are concerned with accepting projects that contain materials that fail to meet specification limits. The research project consisted of a lab study and a field study. The lab study focused on the available alkali test and how fly ash alkali content impacts common performance tests (mortar-bar expansion tests). Twenty-one fly ash samples were evaluated during the testing. The field study focused on the inspection and testing of selected, well documented pavement sites that contained moderately reactive fine aggregate and high-alkali fly ash. A total of nine pavement sites were evaluated. Two of the sites were control sites that did not contain fly ash. The results of the lab study indicated that the available alkali test is prone to experimental errors that cause poor agreement between testing labs. A strong (linear) relationship was observed between available alkali content and total alkali content of Class C fly ash. This relationship can be used to provide a quicker, more precise method of estimating the available alkali content. The results of the field study failed to link the use of high-alkali fly ash with the occurrence of ASR in the various concrete sites. Petrographic examination of the pavement cores indicated that Wayland sand is an ASR-sensitive aggregate. This was in good agreement with Iowa DOT field service records. It was recommended that preventative measures should be used when this source of sand is used in concrete mixtures.

Características físico-químicas do grão de cultivares de arroz em função da adubação nitrogenada

Rice (Oryza sativa L.) stands out as a staple food of the world population due to important nutritional properties. However, rice physico-chemical parameters vary according to genotype and management, for example, the use of nitrogen fertilizer. The aim of this work was to evaluate physico-chemical parameters of grains from thirteen cultivars of upland rice under supplemental sprinkler irrigation and fertilized with different nitrogen rates by topdressing (0, 40, 80, 120 and 160 kg ha(-1)). Parameters such as milling efficiency, commercial grade, gelatinization temperature, as well as total nitrogen and crude protein contents of grains were evaluated. Nitrogen fertilization positively influences the whole grain yield, especially IAC 25 and BRS Colosso. BRS Aroma, IAC 202, IAC 500, BEST 2000, Curinga and Baldo have a high percentage of broken grains. The cultivars Baldo and Carnaroli (appropriate for Italian cuisine), IAC 25 and Caiapo are classified as long grain and the others, as long-thin. The cultivars, except CIRAD 141, displayed grain gelatinization temperature between intermediate and low, providing quick cooking. The grain content protein varies among cultivars, and it can be increased with nitrogen fertilization.

A treatise on soap-making : containing an account of the alkaline materials, test for discovering the presence of an alkali, &c. : with full directions for manufacturing yellow, pure, white, and perfumed hard soap : also, complete instructions for the making of green or soft soap, with other requisites necessary to finish the soap-boiler : to which is added, abstracts of the excise laws relative to hard and soft soap-makers /

Mode of access: Internet.

The alkali fluoride and carbonate bead test for uranium /

"April 1956."

Parametric model for the analysis of concrete expansion due to alkali-aggregate reaction

The alkali-aggregate reaction (AAR) is a chemical reaction that provokes a heterogeneous expansion of concrete and reduces important properties such as Young's modulus, leading to a reduction in the structure's useful life. In this study, a parametric model is employed to determine the spatial distribution of the concrete expansion, combining normalized factors that influence the reaction through an AAR expansion law. Optimization techniques were employed to adjust the numerical results and observations in a real structure. A three-dimensional version of the model has been implemented in a finite element commercial package (ANSYS(C)) and verified in the analysis of an accelerated mortar test. Comparisons were made between two AAR mathematical descriptions for the mechanical phenomenon, using the same methodology, and an expansion curve obtained from experiment. Some parametric studies are also presented. The numerical results compared very well with the experimental data validating the proposed method.

Deicer Scaling Resistance of Concrete Mixtures Containing Slag Cement Phase 2: Evaluation of Different Laboratory Scaling Test Methods, TPF-5(100), 2012

With the use of supplementary cementing materials (SCMs) in concrete mixtures, salt scaling tests such as ASTM C672 have been found to be overly aggressive and do correlate well with field scaling performance. The reasons for this are thought to be because at high replacement levels, SCM mixtures can take longer to set and to develop their properties: neither of these factors is taken into account in the standard laboratory finishing and curing procedures. As a result, these variables were studied as well as a modified scaling test, based on the Quebec BNQ scaling test that had shown promise in other research. The experimental research focused on the evaluation of three scaling resistance tests, including the ASTM C672 test with normal curing as well as an accelerated curing regime used by VDOT for ASTM C1202 rapid chloride permeability tests and now included as an option in ASTM C1202. As well, several variations on the proposed draft ASTM WK9367 deicer scaling resistance test, based on the Quebec Ministry of Transportation BNQ test method, were evaluated for concretes containing varying amounts of slag cement. A total of 16 concrete mixtures were studied using both high alkali cement and low alkali cement, Grade 100 slag and Grade 120 slag with 0, 20, 35 and 50 percent slag replacement by mass of total cementing materials. Vinsol resin was used as the primary air entrainer and Micro Air® was used in two replicate mixes for comparison. Based on the results of this study, a draft alternative test method to ASTM C762 is proposed.

Evaluation of the Duggan Test for Concretes Made of Different Types of Cements, MLR-97-8, 2000

In searching for simple and reliable test methods to evaluate the quality of Iowa portland cement concrete (PCC) pavements, the Duggan test was conducted for concretes made of twenty-six types of cements in this laboratory research. The influence of some factors, such as chemical composition and type of cements, use of air-entraining agent and water reducer, and water to cement ratio, on the result of the Duggan test was examined. It was found that the expansion increases with increasing values of potassium alkali (K2O) and sulfur trioxide (SO3) in cements. It was also found that the Type I cements generally produce higher expansion than the Type II, IP and IS cements. Since it is difficult to identify the major mechanism leading to the expansion observed in the Duggan test, more studies are certainly needed before it can be used as a reliable test method for evaluating the service life of concrete pavement.

Fly Ash Affect on Alkali-Aggregate Reactivity, MLR-88-7, 1989

Cement-aggregate reactions were first reported in the 1940's. Depletion of quality aggregate, changes in cement and the use of fly ash make cement-aggregate reactions a problem still today. This latest research into alkali-aggregate reactivity was initiated to evaluate the new ASTM style test containers and evaluate the effect of Class C fly ash on the expansive reaction. Three aggregates were tested in combination with three cements and three fly ashes available in Iowa. Thirty-six combinations were made and tested over a six-month period. The conclusions were: (1) the new style ASTM containers were much more effective than the containers used by the Iowa DOT in the past; (2) some mixes with 15 percent Class C fly ash had increased expansion over comparative mixes without fly ash; and (3) the Oreapolis #8 pit did not appear to have an alkali-silica reaction problem based on this testing and earlier reported testing.

Limbal autograft transplantation in a dog with alkali-induced ulceration

Descreve-se um caso de um animal da espécie canina, fêmea, sem raça definida, de três meses de idade, com histórico de apatia, contato prévio com produto alcalino (hidróxido de sódio) e relutância em abrir o olho direito. Ao exame oftálmico, foram observados blefarospasmo, fotofobia, epífora, quemose discreta, hiperemia conjuntival, e edema corneal difuso com comprometimento do limbo. Foram realizados o teste da fluoresceína positivo e o Teste Lacrimal de Schirmer 32mm min-1. Com base nos achados, firmou-se o diagnóstico de úlcera por álcali e realizou-se transplante autógeno do limbo. No pós-operatório, observou-se vascularização corneal a partir do terceiro dia e sua intensificação, em número e calibre, nos dias subseqüentes. Também foram observadas mínimas áreas de transparência corneal. Os resultados obtidos permitem admitir que o transplante autógeno de limbo é procedimento factível para o manejo da terapia de úlceras de córnea por álcali.

Topical Brazilian propolis improves corneal wound healing and inflammation in rats following alkali burns

Abstract Background The objective of this study was to investigate the effects of the Brazilian Scaptotrigona sp propolis, a widely used folk medicine, in corneal wound healing and inflammation. Methods Corneal epithelial defects of 1 mm in diameter were made in the right eyes of Wistar male adult rats by cauterization with silver nitrate sticks. Subsequently, they were divided in two groups (n = 40 rats/group): Brazilian propolis (BP) group was topically treated with a microemulsion containing 1% Brazilian propolis; vehicle (VH) group received the same formulation without propolis. The epithelial defect area was photographed and measured at t = 0 (wound induction), and after 12, 24, 48 and 120 h of treatment. The inflammatory response was evaluated based on counting of neutrophils. Epithelial regeneration rates were determined based on Ki-67 expression in basal epithelial cells. Comparisons were made using the Kruskal-Wallis and the Mann–Whitney U test. Results The BP group presented both smaller epithelial defect areas at 12, 24 and 48 h and fewer corneal infiltrating neutrophils at 24 and 48 h (P < 0.01) than the VH group. These effects were associated with more pervasive Ki-67 staining in the BP group at 12 and 24 h (P < 0.05). Conclusions Topically applied BP accelerated wound healing and reduced the inflammatory response to silver nitrate-induced corneal alkali burns in rats.

Evaluation of the activity and stability of alkali-doped metal oxide catalysts for application to an intensified method of biodiesel production

A series of alkali-doped metal oxide catalysts were prepared and evaluated for activity in the transesterification of rapeseed oil to biodiesel. Of those evaluated, LiNO3/CaO, NaNO3/CaO, KNO3/CaO and LiNO3/MgO exhibited >90% conversion in a standard 3 h test. There was a clear correlation between base strength and activity. These catalysts appeared to be promising candidates to replace conventional homogeneous catalysts for biodiesel production as the reaction times are low enough to be practical in continuous processes and the preparations are neither prohibitively difficult nor costly. However, metal leaching from the catalyst was detected, and this resulted in some homogeneous activity. This would have to be resolved before these catalysts would be viable for large-scale biodiesel production facilities.

Engineering properties of alkali-activated natural pozzolan concrete

The development of alkali-activated binders with superior engineering properties and longer durability has emerged as an alternative to ordinary portland cement (OPC). It is possible to use alkali-activated natural pozzolans to prepare environmentally friendly geopolymer cement leading to the concept of sustainable development. This paper presents a summary of an experimental work that was conducted to determine mechanical strength, modulus of elasticity, ultrasonic pulse velocity, and shrinkage of different concrete mixtures prepared with alkali-activated Iranian natural pozzolans—namely Taftan andesite and Shahindej dacite, both with and without calcining. Test data were used for Taftan pozzolan to identify the effects of water-binder ratios (w/b) and curing conditions on the properties of the geopolymer concrete, whereas the influence of material composition was studied by activating Shahindej pozzolan both in the natural and calcined states. The results show that alkali-activated natural pozzolan (AANP) concretes develop moderate-to-high mechanical strength with a high modulus of elasticity and a shrinkage much lower than with OPC.

Mechanical behaviour at high temperature of alkali-activated aluminosilicates (geopolymers)

This study was designed to determine the effect of temperature on the mechanical strength (in both in vivo and post-exposure trials) of two alkaline cements (without OPC): (a) 100% fly ash (FA) and (b) 85% FA + 15% bauxite, the activated alkaline solution used was 85% 10-M NaOH + 15% sodium silicate. A Type I 42.5 R Portland cement was used as a control. Two series of trials were conducted: (i) in vivo trials in which bending and compressive strength, fracture toughness and modulus of elasticity were determined at different temperatures; and (ii) post-firing trials, assessing residual bending and compres-sive strength after a 1-h exposure to high temperatures and subsequent cooling. The findings showed that from 25 to 600 C, irrespective of the type of test (in vivo or post-firing), compressive mechanical strength rose, with the specimens exhibiting elastic behaviour and consequently brittle failure. At tem-peratures of over 600 C, behaviour differed depending on the type of test: (i) in the in vivo trials the high temperature induced pseudo-plastic strain and a decline in mechanical strength that did not necessarily entail specimen failure; (ii) in the post-firing trials, compressive strength rose.

Adapting The Sniffin' Sticks Olfactory Test To Diagnose Parkinson's Disease In Estonia.

The aim of the study was to develop a culturally adapted translation of the 12-item smell identification test from Sniffin' Sticks (SS-12) for the Estonian population in order to help diagnose Parkinson's disease (PD). A standard translation of the SS-12 was created and 150 healthy Estonians were questioned about the smells used as response options in the test. Unfamiliar smells were replaced by culturally familiar options. The adapted SS-12 was applied to 70 controls in all age groups, and thereafter to 50 PD patients and 50 age- and sex-matched controls. 14 response options from 48 used in the SS-12 were replaced with familiar smells in an adapted version, in which the mean rate of correct response was 87% (range 73-99) compared to 83% with the literal translation (range 50-98). In PD patients, the average adapted SS-12 score (5.4/12) was significantly lower than in controls (average score 8.9/12), p < 0.0001. A multiple linear regression using the score in the SS-12 as the outcome measure showed that diagnosis and age independently influenced the result of the SS-12. A logistic regression using the SS-12 and age as covariates showed that the SS-12 (but not age) correctly classified 79.0% of subjects into the PD and control category, using a cut-off of <7 gave a sensitivity of 76% and specificity of 86% for the diagnosis of PD. The developed SS-12 cultural adaption is appropriate for testing olfaction in Estonia for the purpose of PD diagnosis.

Effect Of Exercise Test On Pulmonary Function Of Obese Adolescents.

to investigate the pulmonary response to exercise of non-morbidly obese adolescents, considering the gender. a prospective cross-sectional study was conducted with 92 adolescents (47 obese and 45 eutrophic), divided in four groups according to obesity and gender. Anthropometric parameters, pulmonary function (spirometry and oxygen saturation [SatO2]), heart rate (HR), blood pressure (BP), respiratory rate (RR), and respiratory muscle strength were measured. Pulmonary function parameters were measured before, during, and after the exercise test. BP and HR were higher in obese individuals during the exercise test (p = 0.0001). SatO2 values decreased during exercise in obese adolescents (p = 0.0001). Obese males had higher levels of maximum inspiratory and expiratory pressures (p = 0.0002) when compared to obese and eutrophic females. Obese males showed lower values of maximum voluntary ventilation, forced vital capacity, and forced expiratory volume in the first second when compared to eutrophic males, before and after exercise (p = 0.0005). Obese females had greater inspiratory capacity compared to eutrophic females (p = 0.0001). Expiratory reserve volume was lower in obese subjects when compared to controls (p ≤ 0,05). obese adolescents presented changes in pulmonary function at rest and these changes remained present during exercise. The spirometric and cardiorespiratory values were different in the four study groups. The present data demonstrated that, in spite of differences in lung growth, the model of fat distribution alters pulmonary function differently in obese female and male adolescents.