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The article provides information on SGI, a Standard Industries company, acquiring Panamint Valley Limestone (PVL), a southern California-based quarry known for mining limestone used in building materials and other applications.

Presents several architectural furnishings. Quality of limestones coming from Haifa company; Capability of the gyro fan from G Squared Arts; Features of the Pog system from B&N Industries.

The suitability of dolomite-rich carbonate rocks as a cement main constituent and thus for the production of highperformance cements and concretes of high durability was investigated. Four Portland cements were combined with five carbonate rocks containing different dolomites and a calcite-rich limestone as reference material, to investigate a total of thirty CEM ll/A cements with 20 mass % and CEM ll/B with 30 mass % of the carbonate constituent. The dolomite content of the carbonate rocks was between 67 and 98 mass %. Fresh and hardened concrete properties were tested. The focus was on studies on frost resistance. It turned out that all tested dolomite-rich carbonate rocks have shown a comparable high-performance with the calcite-rich reference limestone. Differences of Portland cement (clinker) properties had a greater impact on the cement and concrete performance than the differences between the five dolomite containing carbonate rocks. Based on the results of the investigation, dolomite-rich carbonate rocks could also be used as a cement main constituent as well as limestones defined in the current cement standard. A corresponding change in the cement standard would enable cement producers to use also dolomitic limestone resources in their quarries in future. [ABSTRACT FROM AUTHOR]

The article highlights benefits of limestone mine's dust strategy for controlling limestone dust in mining operations. It mentions that limestone is considered as dustiest substance in cement production process. It also mentions about Continental Cement Co. which understands impact of fugitive dust emissions on workers. It also mentions that cost of cement industry dust to society and workers has been studied in depth by U.S. Environmental Protection Agency (EPA) to justify dust regulations.

Using numerous limestones, the impact of limestone specific parameters on the properties of the derived Portland limestone cements (CEM II/A- and CEM II/B-cements with 15 or 30 mass % of limestone) and the durability of concretes made of these cements, has been investigated. Parameters were the geologic origin, microstructural characteristics and the mineralogical composition, especially the secondary phases beside calcite. The limestone samples basically differed in the calcium carbonate content. All limestones met the standard requirements acc. to EN 197-1 for TOC content and methylene blue adsorption, but not always for the calcium carbonate content. The different calcium carbonate contents of the limestones had no significant impact on the microstructure, porosity and compressive strength development of the Portland limestone cement mortars investigated. However, parameters like particle size of the cement component and the limestone content were of great importance. However, differences in the mineral phases and their distribution in the limestone microstructure influenced certain durability properties of the concretes made with CEM ll/B cements containing limestone. Non-standard compliant limestones with high dolomite content resulted in consistently good concrete durability, and those with low quartz to clay mass ratio in mostly appropriate concrete durability. [ABSTRACT FROM AUTHOR]

Conventional use of binary blended cement has been fast changing towards a composite cementitious system which enables the use of two or more substitute materials in conjunction. Limestone and calcined clay cement (LC3) is one such promising blend of composite cement. This ternary combination can significantly improve the substitution level of clinker with good mechanical characteristics. This is owing to the fact that limestone in the presence of calcined clay results in the new chemistry with the formation of additional hydrates. This paper discusses the phase assemblage at different hydration stages in the LC3 cementitious system up to 28 days.The X-ray diffraction technique was used to study the phases in the Ordinary Portland cement, Portland Pozzolana cement and LC3 to understand the phases and their evolution in the different systems. XRD confirmed the formation of a carboaluminate phase at an early age. This phase seemed to remain stable up to 28 days. A semi-quantitative estimate suggests an increase in the amount of ettringite (AFt) phase due to stabilization of this phase in the presence of limestone. The amount of bound water was also evaluated for the different hydrated systems. Further, faster depletion of portlandite was observed in the system due to calcined clay's high reactivity and synergistic hydration kinetics in the LC3 blend. [ABSTRACT FROM AUTHOR]

The article discusses the application of ammonia as a viable alternative to address limitations with respect to liquid and solid waste generation and handling. It mentions that lime or limestone are widely used chemical reagent throughout the world for sodium oxide emissions control at coal-fired power plants. It notes that the Efficient Ammonia-Based Desulfurization Technology (EADS) does not generate any liquid waste streams or undesirable solid byproducts that require disposal.

ln addition to the higher requirements for lime quality, the investment and operating costs play a critical role in the dimensioning and optimization of lime rotary kilns. In order to optimize existing rotary kilns and to design new furnaces with respect to economic factors, the calcination process needs to be carried out precisely. Experience regarding the effect of changing significant process parameters is especially vital. For this reason, a mathematical model was developed to simulate the process of lime burning in directly fired rotary kilns. In this model, the temperature, reaction and filling degree curves along the rotary kiln are calculated and additional data regarding the exhaust gas composition, heat loss through the wall, the specific energy demand and the lime quality are determined. In the first phase, a model is developed for an industrial rotary kiln that is fired with lignite. In the bounds of a parameter study, the effects of adjustments to the natural gas firing on the lime quality are shown. The potential of this simulation model is presented with the aid of further parameter variation with the goal of process optimization after the fuel substitution process. Here, the influences of the primary energy input and the throughput rate are especially clearly shown. [ABSTRACT FROM AUTHOR]

A new method has been developed at the Institute for Non-Metallic Materials at Clausthal University of Technology that, under given burning conditions, makes it possible to estimate the degree of alite formation that is dependent on the heterogeneity. The raw meal homogeneity is obtained using focused X-ray radiation and then quantified by a new procedure. The expected degree of alite formation is derived as the quotient of the alite content determined in the laboratory burning test and the thermodynamic equilibrium. Associated with this is the aim to achieve a higher alite yield by measures to refine and homogenize the raw meal, [ABSTRACT FROM AUTHOR]

The article focuses on several features of limestone which is a carbonate sedimentary rock made up of skeletal fragments from marine organisms. It mentions uses of limestone include such as conditioner to neutralize acidic soils, cement and mortar ingredient and filter to remove impurities in steel blast furnaces. It also mentions Vortex Global designs and manufactures slide gates, diverter valves and loading solutions specifically intended and modified to handle liming materials.

The article reports that Cemex's vast Balcones quarry near New Braunfels, Texas, started operations in 1968 and is one of the top aggregate operations in the U.S., producing around 10 to 12 million tons of limestone materials. It notes that the system decreases the company's environmental impact and reliance on water pulled from nearby sources by using 90 percent less water annually. The new wash plant features Schurco slurry pumps and National Pump vertical turbine pumps.

Clay minerals, which can be contained in aggregates or in limestone meal, reduce the flowability of concretes by absorption (consumption) of water. Superplasticizers also settle on the surfaces of the clay particles and are then no longer available for plasticizing the cement paste. Polycarboxylates in particular can also be incorporated in the chemical structure of the clay mineral montmorillonite (bentonite) and in this way are removed from the cement paste so that their plasticizing action is partially or even entirely lost. The negative effects of clay minerals can be lessened or completely eliminated by using clay-resistant PCE superplasticizers, by supplementary addition of cationic compounds or by "sacrificial substances". [ABSTRACT FROM AUTHOR]

A description is given of the test results from experiments for determining the influence of the shape of the feed material on the target variables during single particle impact comminution. For this purpose differently shaped pieces of limestone, granite and glass were submitted to single particle stressing in the trials. An HASA high resolution impact analyzer was used to investigate the process. This analyzer was used to determine variables such as the contact force and contact time for characterizing the intensity of loading and as a measure of the dynamic loading of mechanical elements in machines for impact comminution. The energy consumption and comminution technology variables were also determined. During the analysis of the results it became clear that the particle shape of the feed material has a strong influence on the target variables mentioned, with the result that the findings could be formulated into various statements. For example, the measured contact force during the comminution of spherical particles was up to 100 % higher than during the comminution of irregular, extremely flat, particles. It was also established that the contact time between impact bar and particle increases with increasing elongation or flatness of the feed material particles but falls with increasing cubicity. The results obtained from the single particle impact trials not only provide useable findings for the design and construction of impact crushers but also give the plant operators information about the quality of the comminution product and the energy utilization that can be expected in relation to the surface area. [ABSTRACT FROM AUTHOR]

Limestone has been extracted very successfully from the "Laybruch" deposit for more than 155 years for Schaefer Kalk GmbH & Co. KG at Hahnstätten. Over the coming years this is to be gradually replaced by the "Merschelbruch" deposit. Schaefer Kalk has installed a new crushing plant with downstream processing plant at the edge of the new deposit to ensure the customary high product quality. Initial planning started in 2003 during the authorization procedure to open up this deposit. Construction began in 2013 after the planning process was re-started in 2011. Trial operation began in early 2015. 180000 m3 earth were removed to develop the working area and conveyor belt routes and 9500 m3 concrete, 14501 reinforcing steel and 5001 structural steel were used to construct the requisite building. The planning jurisdiction for the entire project was handled by Schaefer Kalk so all the trades and machine suppliers could be coordinated centrally. This meant that it was also possible to secure the optimum design for all machines and plants and to design a basic version of the entire plant that could be extended modularly, with a material turnover of 350 t/d that can be increased to up to 500 t/h in the coming years by increasing the efficiency. From the individual machines and the sometimes unique closed control systems of the units that were supplied it was possible to generate an optimum higher-level control system and visual display. All the information needed for monitoring is supplied directly to the operator through the central process control system. [ABSTRACT FROM AUTHOR]

Lime sales in recent years have been increasingly dominated by stricter demands on product quality and costs with respect to specific energy consumption and the use of crushed limestone with a wide size spectrum. Parallel Flow Regenerative kilns are now used very widely throughout the world for producing lime. As a leading provider of this type of kiln Cimprogetti recently introduced the Vanguard high performance lime kiln to the lime industry with daily outputs of up to 700 t/d. Since then the company has been constantly concerned with gathering information about the choice of limestone and the process engineering aspects of kiln design with the aim of using limestone with the widest possible size range, improving the fuel distribution and preventing material segregation. A suitable material charging system has been developed to improve the kiln process, especially with respect to large kiln units. A new scientific approach for technical evaluation of the existing kiln charging system was started in conjunction with Italian universities in which the size composition of the raw limestone is included in the analysis. The investigations were carried out using Rocky-DEM, a 3D Discrete Element Modeling (DEM) software. The following information was obtained: the newly developed kiln charging equipment is less complicated and involves lower maintenance costs; reduced use of chutes within the charging system can minimize segregation of the material; generation of dust is substantially reduced by consistent use of the enclosed charging system; the new kiln charging equipment can also be used with existing lime kilns that exhibit critical segregation behaviour and must be optimized with respect to the quality of lime produced. [ABSTRACT FROM AUTHOR]

The vertical roller mill has proved to be a universal solution for finish grinding of all typical materials processed in a cement works, such as limestone, coal, clinker and blastfurnace slag. The maximum mill power used for driving the grinding table doubled from 2.5 MW in the mid 1970s to 5 MW in the 1990s. Today, 20 years later, a drive power of about 10 MW is required, with a tendency to increase still further. As in other industries, the size of the units is increasing and the requirement for equipment availability is becoming more and more important. In the past, the gear technology had always developed in step with the mill power. In the first generation of drives, featuring bevel gears with parallel shafts, torque splitting was required when the torque exceeded 1 million Nmt. The second generation of drives, featuring a planetary output stage, emerged in 1979. The current state-of-the-art three-stage bevel-planetary gear unit represents the third generation for driving the grinding tables of vertical roller mills. In the meantime, new fourth generation gear strategies for coping with the increasing torques have been proposed and tested - always with the aim of improving key performance features still further. The newly developed Renk Integral Multi-Motor (two stage) gear drive named COPE (Combined Planetary Electric drive) combines the various advantages of the other 4th generation strategies. This paper will explain the advantages to the cement industry of applying this new drive solution. The aim is to demonstrate the important gains in reliability, reduction in downtime and, last but not least, the saving in time for planning and commissioning the grinding plant. [ABSTRACT FROM AUTHOR]

The provision of limestone for producing high-grade lime products does not entail any serious difficulties if a homogeneous deposit that satisfies the quality requirements is available. This basic requirement is not always fulfilled so it is also necessary to work limestone deposits that may be contaminated and inhomogeneous. Operating experience and possible ways of improving existing processes and measures are described while taking the appropriate literature into account. The aim is to ensure, and where necessary to improve, the quality of the limestone when excavating inhomogeneous deposits, to make the operating sequences as rational as possible and to make optimum use of the available deposits. The methods and suggestions that are quoted are based to some extent on in-house experience and considerations. From these it will be possible to derive solutions for forthcoming problems that will intensify in the future. Some suggestions may be considered unconventional but should be examined critically and, if appropriate, tested. It must be assumed that the conditions under which mineral raw materials have to be provided will become more difficult in the long term. Some possible solutions are offered by modern sorting procedures of the type already used in numerous branches of industry. [ABSTRACT FROM AUTHOR]

The article offers information on the Annual General Meeting of the Federal German Association of the Lime Industry about the environmental aspects of limestone and lime products that took place in the Hotel Europäischer Hof in Heidelberg, Germany on June 13, 2014.

KHD Humboldt Wedag, operating as the main contractor, has built a cement works consisting basically of two identical cement production lines with a projected clinker capacity of 2 × 3 000 t/d in the southern Ural region near the town of Novotroitsk. The scope of supply and services ranged from limestone transport and the clay crushing plant to cement grinding and the cement packing and loading plant as well as the entire process control for the works. The first cement production line became operational in 2010 while the second line is to be commissioned in the second quarter of 2013. The special feature of this new cement project is the utilization of mineral by-products from the neighbouring iron and steel industry. Up to 30 % blastfurnace slag is employed in addition to the main raw materials, namely limestone and a clay component, as well as Siemens-Martin slag as a corrective component. Thanks to this approach the cement works is making an outstanding contribution to improving the environment. The use of blastfurnace slag in the raw material mix produces a significant reduction not only in the CO2 emissions from the cement works but also in the specific heat consumption of both kiln lines. A heat consumption of 2 495 kJ/kg was measured during the performance test of the kiln that is already in operation. The strategy for both production lines was developed by the ZAB Zementanlagenbau GmbH Dessau, which as a wholly owned subsidiary of KHD Humboldt Wedag also undertook the supply of the basic design engineering, the principal technical equipment, supervision of the installation and commissioning of the plant, as well as the training of the OOO JUGPK staff. [ABSTRACT FROM AUTHOR]

Rapid expansion of the cement industry, development of new technology and the economic situation have resulted in expansion and construction of high capacity cement plants. This requires large quantities of cement-grade lime- stone, either from a single quarry or from several quarries at different locations. It is difficult to produce blended limestone from quarries at different locations because of the challenges presented by different geological formations, different grades of material in the different quarries, etc. Any change in raw mix with respect to limestone quality or quantity, will have an impact on long-term strategic resource planning due to the quantities of different grades from the different quarries. The authors have attempted to provide a long-term strategic plan for optimization of quarry planning and production scheduling for four limestone quarries some distance apart. The limestone deposit involves varying thicknesses of argillaceous limestone interspersed with highly siliceous limestone, with underlying shale in some of the quarries. Quarry production schedules for the blended limestone have been prepared for all the four quarries with the help of Multimine Scheduler software to achieve an optimum economical extraction sequence with minimum quality variation and an effective optimum on site/multi-site blending scheme. An Optimal Extraction Sequence (OES) for model quarries has been generated to create a workable quarrying plan that takes account of the effects of quarrying constraints to produce practical quarry designs and achievable quarrying schedules. As a result, it has been possible to achieve the raw (run-of-mine) limestone grade with a specified CaO and SiO2 content and a target annual production rate with enhanced quarry life. [ABSTRACT FROM AUTHOR]

Raw materials for a cement plant, such as limestone, marl, chalk or similar, usually come from a nearby quarry. The trend towards cost efficient sourcing for fuels and additives, however, leads to the exploitation of a growing number of sources often spread all over the world, with varying material characteristics. However, new kilns even require a feed material quality of increased consistency to achieve high product quality and process efficiency. This leads to new challenges for material blending and homogenizing. The example of a coal handling system at a cement plant with the coal provided by road trucks from up to eight different small mines with a wide variety of coal characteristics is used to discuss the challenges related to the requirement of high product homogenization, both from the point of view of the stockyard designer and the equipment supplier. [ABSTRACT FROM AUTHOR]

The article features Mark Madson, president of Little Limestone Inc., producer of limestone and aglime in Clinton, Wisconsin. The company was started by his stepfather in 1952 and in 1970 he acquired his own parcel where he set up a permanent crushing and screening operation. The operation is a father-and-son kind of operation where they engineered most of the plant themselves, built the stacking conveyors and screen boxes. His antics have been chronicled in a book "The Wisconsin Madman."

The influence of four PCE-based superplasticizers (synthesized selectively in the laboratory) on the shear resistance, especially at the saturation point, of cement pastes was investigated at the FIZ (Research Institute of the Cement Industry) using two commercially available cements. The intention was to clarify whether, and possibly from which parameters of the molecular structure of the PCE (polycarboxylate ether), it is possible to deduce a general mode of operation in conjunction with different cements. Rheological investigations of the shear resistance, especially at the saturation point, were compared with zeta potential measurements. The influence of two limestones and two granulated blastfurnace slags on the zeta potential and the shear resistance of laboratory cements produced with them, as well as on the adsorption of a commercially available PCE, was also examined. For the cements investigated the PCEs with high charge densities were relatively independent of the lengths of the side and main chains with respect to reaching the saturation point most effectively. The duration of the plasticizing action on the saturation point did not always correlate with the lengths of the side chains. The shear resistance fell with increasing quantity of active substance and the zeta potential was displaced in the direction of the isoelectric point (0 mV) due to the displacement of the shear plane caused by adsorption of the PCE. There was a correlation between the quantity of active substance adsorbed, the zeta potential and the shear resistance. The saturation point was determined both with the aid of rheological measurements of the shear resistance and by determining the zeta potential. The limestones and granulated blastfurnace slags investigated were able to adsorb sulfate ions from the pore solution, resulting in a negative zeta potential. Competitive adsorption between sulfate ions and plasticizer molecules is therefore also to be expected with these components. Increasing the proportion of granulated blastfurnace slag led to a significant drop in the shear resistance of the cement pastes and displacement of the zeta potential in the direction of the isoelectric point. The limestones used affected the shear resistance and the zeta potential of the cement paste to different extents and more significantly than the granulated blastfurnace slags investigated. [ABSTRACT FROM AUTHOR]

The article presents information on techniques for determining limestone composition and reactivity. Accurate determination of limestone composition and reactivity are stated to be crucial in the selection of reagents for WFGD applications. It is stated that X-Ray Fluorescence (XRF) is a cost-effective technique for elemental analysis.

The article profiles Robertson Crushed Stone, a family-owned business based in Milltown, Indiana that produces high-quality limestone. The quarry face of the company yield a limestone that is rich in calcium carbonate and low in magnesium which is ideal for scrubber stone used to remove sulfur dioxide from power plat emissions. The company created a niche market selling aggregates to power plants. Two of the biggest customers of the company are the Gibson Station of Duke Energy in Princeton, Indiana and Indianapolis Power & Light in Petersburg, Indiana.

The article discusses the operations and history of Clinton Point Quarry of Tilcon New York. Clinton Point Quarry, which is located in Poughkeepsie, New York, produces an average of 5 million tons of dolomitic limestone per year. The aggregate, which is being supplied to areas near the Hudson River Valley, Long Island and New York City, is used for road and building construction. The quarry used to be a part of the estate of George Clinton, the first governor of New York State. A comparison of the operations during the 1930s and that of 2008 is made.

The article offers facts about the circulating fluidized bed technology (CFB). A key advantage of the technology is that pollution control is built right into the combustion process and by adding low-cost limestone into the CFB, SOx is captured and removed right at the point where it is formed as the fuel burns. The ability to burn so-called opportunity fuels makes the CFB something an opportunity technology and those opportunities include fuel diversity that extends to renewable fuel sources. It reveals that CFB are amenable to burning higher percentages of biomass than pulverized coal units which are limited to co-firing about 10% biomass. INSET: HANDLING CFB FUEL.

The article focuses on the need for the electric power industry to address various issues about flue gas desulfurization (FGD) water treatment. It is inferred that the composition of FGD varies widely based on scrubber type and coal and limestone used. The contribution of coal to FGD includes acidic gases such as chlorides, fluorides, and sulfate, while the contribution of limestone include clay minerals such as aluminum. Several stages are required to treat wastewater blowdown from the FGD scrubber to comply with the National Pollutant Discharge Elimination System requirements for surface water discharge.

The article focuses on several aspects of gaining the entitlement for conducting any type of mining operation in California. It mentions need for establishing a record of land use and ownership's intent to continue mining, and then gaining acceptance of facts by the local lead agency. It also mentions that questions relating to code interpretations are typically directed to the planning director for a determination.

The article discusses wet-limestone scrubbing. Environmental regulations are causing many facilities to install flue gas desulfurization systems to control sulfur dioxide emissions. Wet-limestone scrubbing is a classic example of an acid-base chemistry reaction utilized on a large industrial scale. It details the improvements made in scrubber vessel construction material. It addresses the issue of byproduct disposal.

Features the Rector's Office at the New University of Lisbon in Portugal. Description on the architectural design of the building; Area of the office; Use of pale limestone.

The article talks about the shipments of limestone on the Great Lakes increasing according to Lake Carriers Association, shipments from the quarries of the United States and representing companies of the United States and carry raw materials.

The article talks about the limestone quarry, Delta Companies partnering with Volvo Construction Equipment, the company specializing in asphalt paving and road constructions, planning for the future and accessing manufacture's site assessment program. It talks about focusing on overburden project, ways to develop haul roads, using Volvo EC750E excavator for the overburden removal, looking into operations and maximizing profitability.

The article discusses how coal-fired plants in the U.S. benefit from using non-traditional pulverized limestone reagent in their wet limestone flue gas desulfurization (GFD) systems. Southern Co. is one of electric utilities that explored the use of pre-processed limestone reagent. Some of the benefits of non-traditional pulverized limestone supply are capital savings, reduced parasitic power consumption, independence of limestone supply, and reduced environmental impact.

The article reviews the Hyperwave limestone collection from Testi.

The article offers information on the use of advanced process control to improve the efficiency of wet limestone scrubbing for flue gas desulfurization (FGD) in coal-fired power plants. It says that the optimization process reduces the number of pumps and limestone slurry used for sulfur dioxide (SO2) reduction. It adds that the optimization method is made up of three functions such as enhanced regulatory control, process value prediction, and model-based prediction.

The article announces that company Pattison Sand in Iowa will soon commission a $2,200,000 tunnel feeder plant to allow the direct loading of dolomitic limestone into rail cars, without requiring additional material handling, manpower, and equipment.

The article reports that Quikrete Cos. provided the mortar used to lay block and stone for the National Museum of the American Indian (NMAI), which opened last fall in Washington, D.C. The museum is a five-story domed structure that has the appearance of a gigantic natural rock formation and is accented by curving bands of rough-cut, golden-toned limestone. The project required the use of 1,935 Quikrete 3,000-pound bags of Type S mortar and its Spec-Mix silo system to lay block backup on the 250,000-square-foot NMAI. The project took three years, involved more than 40 masons, and required two custom-blended colors, which were individually mixed into the mortar for wet-setting stone.

The Portland Cement Association has outlined a proposal to allow for the inclusion of up to 5 percent ground limestone in the Portland cement standard designated as ASTM C150. The proposed change would bring U.S. standards up to those in Europe and Canada. The benefits include a reduction in the use of raw materials, and reduced energy consumption and greenhouse gas emissions.

The article offers brief information on various products including Adair Georgian Blend Limestone, the ActiveSmart Foodcare refrigerator and the GPX FireFloor System from architecture, refrigeration and safety companies ArrisCraft, Fisher & Paykel Appliances Holdings Ltd. and Safti First.

The article reports the rise in the popularity of a low-carbon containing cement called Limestone Calcined Clay Cement (LC3), which is a new blend of limestone and calcined clay, in the developing markets of South America. Details on the LC3 development project which focuses on carbon dioxide mitigation and the opinion of the research and technical services vice-president at the Portland Cement Association, Steven Kosmatka on the matter, are presented.

The article offers aggregate industry news briefs in the U.S. as of November 2017. Topics of the news include the launch of a limestone transportation service by ready-mix concrete and building materials firm Chaney Enterprises through its new railway, the signing of an acquisition agreement of building materials firm Polaris Materials Corp. made by concrete materials provider U.S. Concrete Inc. and the performance of economic indicators for construction and building materials firms.

Cements with a Portland cement clinker content of about 50 mass %, using granulated blastfurnace slag and limestone as other main constituents, are suitable in principle for producing structural concretes. In laboratory tests within the framework of the currently valid descriptive regulations of DIN 1045-2 these concretes have shown fresh concrete properties as used in practice, good mechanical properties and - with the exception of the resistance to freeze-thaw with or without de-icing agents - permissible durability properties. [ABSTRACT FROM AUTHOR]