scholarly journals Reaction of Converter Slag with Supercritical Carbon Dioxide and Its Potential Applicability as Aggregate for Concrete

2021 ◽  
Vol 11 (4) ◽  
pp. 1918
Author(s):  
Hoon Moon ◽  
Kyeongtae Kim ◽  
Ji-Hyun Kim ◽  
Minhee Lee ◽  
Chul-Woo Chung
Keyword(s):  
Supercritical Co2 ◽  
Converter Slag ◽  
Concrete Aggregate ◽  
Co2 Uptake ◽  
Free Lime ◽  
Aggressive Environment ◽  
Long Period ◽  
Aging Period ◽  
Potential Applicability ◽  
Mortar Bar

The presence of free lime and periclase in converter slag prevents it from directly being utilized as a source of concrete aggregate due to the deleterious expansion caused by reaction of free lime and periclase. In general, a six-month aging period is suggested in order to avoid any potential problems, but it is a tedious process that requires a long period of time. In this work, supercritical CO2 (SCD) was used to reduce the aging period down to one day or so. Since SCD creates a more aggressive environment for reaction, it can directly attack the surface of free lime and periclase to induce expansive reaction before using converter slag as concrete aggregate. According to the experimental results, the surface of converter slag was successfully carbonated by SCD, showing 7.80% of CO2 uptake by weight of converter slag. It was found that the mortar bar made of reacted converter slag reduced the amount of expansion. The 28-day compressive strength of mortar with converter slag was slightly reduced after reaction with SCD, but it was still 32% higher than mortar made of conventional sand.

scholarly journals Assessment of Postmortem Aging Effects on Texas-style Barbecue Beef Briskets

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
McKensie K. Harris ◽  
Ray R. Riley ◽  
Ashley N. Arnold ◽  
Rhonda K. Miller ◽  
Davey B. Griffin ◽  
...  
Keyword(s):  
Force Measurements ◽  
Internal Temperature ◽  
Aging Effects ◽  
Oak Wood ◽  
Long Period ◽  
Aging Period ◽  
Postmortem Aging ◽  
Salt And Pepper

Palatability traits (tenderness, juiciness, flavor, and overall liking) of beef briskets (n = 48) were evaluated for 3 different postmortem aging period comparisons: 7 d vs. 21 d (Set 1), 21 d vs. 35 d (Set 2), and 7 d vs. 35 d (Set 3). Briskets were prepared as Texas-style barbecue by seasoning with salt and pepper and smoking with oak wood over a long period (approx. 11 h) using a commercial oven designed for such purposes until deemed tender (approx. 85°C internal temperature). Within each treatment set, Warner-Bratzler shear (WBS) force measurements did not differ (P > 0.05) between aging days; however, WBS force measurements for point (Mm. pectorales superficiales composed of the M. pectoralis transversus and M. pectoralis descendens) were lower (P < 0.05) compared to the flat portions (M. pectorals profundus) within each aging set. Consumer panelists did not (P > 0.05) detect differences between aging days within each set for overall liking, flavor liking, tenderness liking, and juiciness liking. Conversely, differences were found between brisket point and flat portions; Set 1 differed for flavor liking (flat > point; P = 0.0348) and juiciness liking (point > flat; P = 0.0004), Set 2 differed for overall liking (flat > point; P = 0.0499) and juiciness liking (point > flat; P < 0.0001), and Set 3 differed for overall liking (flat > point; P = 0.0296) and juiciness liking (point > flat; P = 0.0112). Our findings indicate postmortem aging did not improve beef brisket palatability, but we did note differences between point and flat portions. Preparing beef briskets as Texas-style barbecue resulted in products with low WBS values and high consumer palatability ratings, which helps demonstrate why barbecued briskets are so popular.

scholarly journals Effect of lithium nitrate on the reaction between opal aggregate and sodium and potassium hydroxides in concrete over a long period of time

2017 ◽  
Vol 65 (6) ◽  
pp. 773-778 ◽  
Author(s):  
J. Zapała-Sławeta ◽  
Z. Owsiak
Keyword(s):  
Electron Microscopy ◽  
Pore Solution ◽  
Alkali Silica Reaction ◽  
Lithium Nitrate ◽  
X Ray ◽  
Long Period ◽  
Chemical Admixtures ◽  
Mortar Bar ◽  
Sodium And Potassium ◽  
Scanning Electron

AbstractAlkali-silica reaction (ASR) is a reaction between amorphous or poorly crystallized siliceous phase, present in aggregates, and sodium and potassium hydroxides in the pore solution of concrete. Chemical admixtures such as lithium compounds are known to have high potential of inhibiting ASR. The aim of this study was to determine the effect of lithium nitrate on ASR in mortars containing high reactive opal aggregate over a long period of time. Mortar bar expansion tests were performed and microstructures of mortar bars were observed by scanning electron microscopy coupled with an energy dispersive X-ray microanalyser. Results from this study showed that effectiveness of lithium nitrate in mitigating ASR was limited over a long period of time. A larger amount of ASR gel which was formed in the presence of lithium nitrate indicated that the deterioration processes intensify within longer periods of time, which so far has not been observed in literature. Microscopic observation confirmed the presence of alkali-silica gel and delayed ettringite in mortars with lithium nitrate.

Evaluation of Electric Arc Furnace Oxidizing Slag Aggregates Quality and Development of Functional Concrete

2019 ◽  
pp. 112-125
Keyword(s):  
Chemical Properties ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Concrete Aggregate ◽  
Arc Furnace ◽  
Aging Period ◽  
Volume Weight ◽  
Expansion Mechanism ◽  
Free Cao ◽  
Physical And Chemical

Chapter 8 evaluates a most interesting and up-to-date topic of electric arc furnace oxidizing slag as aggregates' quality and development of functional concrete. A comprehensive introduction is given followed by a scientific method of stabilizing electric arc furnace (EAF). Oxidizing slag (EOS) is explained in brief. Subsequently, expansion mechanism of EOS and physical and chemical properties of EOS aggregates are covered in reasonable detail. A method for quantitative evaluation of free CaO contained in EOS that covers free CaO content as a function of aging period and open storage position for EOS and ERS samples are explained. Results indicated that the functional concrete using EOS aggregates satisfied the standards of slump, amount of air, its unit volume weight, and compressive strength. Moreover, x-ray irradiation experiment confirmed that the functional concrete using EOS aggregates showed a shielding performance approximately 20% higher than the typical concrete. These results verify that EOS has sufficiently good properties for use as concrete aggregate.

Accelerated Mortar Bar Test Precision with Recycled Concrete Aggregate

2018 ◽  
Vol 115 (4) ◽  
Author(s):  
Bryce D. Fiore ◽  
Kenneth Gerow ◽  
Matthew P. Adams ◽  
Jennifer E. Tanner
Keyword(s):  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregate ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

scholarly journals Crystallization of Free Lime and Magnesia from Molten LD-converter Slag

1983 ◽  
Vol 69 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Aribumi NIIDA ◽  
Kazuo OKOHIRA ◽  
Arata TANAKA ◽  
Tsuyoshi KAI
Keyword(s):  
Converter Slag ◽  
Free Lime

scholarly journals The Corrosiveness of Muskeg Waters: A Review

1965 ◽  
Vol 2 (4) ◽  
pp. 327-336
Author(s):  
L C MacFarlane
Keyword(s):  
Surface Coating ◽  
Anaerobic Bacteria ◽  
High Alumina ◽  
Ph Measurements ◽  
Metal Structures ◽  
Aggressive Environment ◽  
Long Period ◽  
Free Carbon Dioxide ◽  
Aggressive Attack ◽  
Dissolved Salts

Muskeg waters are generally acidic and potentially corrosive to concrete and metal structures. The amount of dissolved salts and free carbon dioxide in the water is an important factor in its aggressive attack on concrete. Although pH measurements are not the only criterion of aggressiveness, they are a reasonable indication in many instances of potential severity. A good defence against an aggressive environment is a high quality, very dense concrete. High alumina concrete and air-entraining agencies provide further protection in extremely aggressive environments. Surface treatments of concrete have not proved to be very successful over a long period of time.Corrosion of metals in a muskeg environment is an electrochemical action; the type and rate of corrosion are functions of the property of the metal as well as the soil and water conditions. Factors such as dissolved salts, pH, total acidity, resistivity, aeration, and presence of anaerobic bacteria influence corrosion. Optimum protection to metals in an aggressive environment is provided by a combination of a surface coating and cathodic protection.

Wadi gravel – a new concrete aggregate in Qatar: Part 2 –Alkali aggregate reactivity

2019 ◽  
Vol 53 (3) ◽  
pp. 400-412 ◽  
Author(s):  
Ian Sims ◽  
Khaled Hassan ◽  
Murray Reid ◽  
Mohammed bin Saif Al-Kuwari ◽  
Mohamed Attia ◽  
...  
Keyword(s):  
Perceived Risk ◽  
Test Methods ◽  
Petrographic Analysis ◽  
Concrete Aggregate ◽  
Gulf Region ◽  
Rock Types ◽  
Alkali Aggregate Reactivity ◽  
Accelerated Mortar Bar Test ◽  
Bar Test ◽  
Mortar Bar

Deposits of Wadi gravel are available in many parts of the Gulf region, but not widely utilized as aggregate for concrete, mainly due to the possibility of internal sulfate attack, plus the perceived risk of alkali aggregate reactivity (AAR). This paper describes the investigations for AAR of the Wadi gravel in this case, as part of the wider study described in Part 1 of this paper.Wadi gravel from the Mekaines site in Qatar was subjected to petrographic analysis, plus the gel-pat and accelerated mortar-bar test methods. The AAR potential was found to be low to normal. The accelerated mortar-bar test exhibited ‘innocuous’ behaviour after 14 days of immersion in alkali solution. When separately testing the constituent rock types of the Wadi gravel, limestone and quartz returned innocuous results, while rhyolite, granite and quartzite returned potentially alkali silica reactive (ASR) results and some reaction was confirmed using post-expansion petrographic examination.Wadi gravel was classified as potentially reactive in the RILEM AAR-4.1 accelerated concrete prism test, but of ‘low reactivity’ in the BS 812-123 test over the longer period of 12 months. Overcoming the potential problems of gypsum content and AAR successfully provides a valuable local resource of Wadi gravel aggregate for concrete.

On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message
Keyword(s):  
Periodic Solution ◽  
Periodic Solutions ◽  
Large Amplitude ◽  
Restricted Problem ◽  
Small Amplitude ◽  
Minor Planets ◽  
Long Period ◽  
Numerical Integrations ◽  
Period Variations ◽  
The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

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