High Performance and High-Strength Concretes Coursework - 275 Words

High Performance and High-Strength Concretes Coursework (Coursework Sample) Content: High Performance and High-Strength ConcretesHigh-performance concrete is a term used to describe concrete with special properties not attributed to normal concrete. High-performance means that the concrete has one or more of the following properties: low shrinkage, low permeability, a high modulus of elasticity, or high strength. Further, high performance concrete is "concrete that meets special performance and uniformity requirements that cannot always be achieved routinely by using only conventional materials and normal mixing, placing, and curing practices. The requirements may involve enhancements of placement and compaction without segregation, long-term mechanical properties, early-age strength, toughness, volume stability, or service life in severe environments.On the other hand, high-strength concrete is typically recognized as concrete with a 28-day cylinder compressive strength greater than 6000 psi or 42 KN/M (Mpa). More generally, concrete with a uniaxial compressive strength greater than that typically obtained in a given geographical region is considered high-strength, although the preceding values are widely recognized. Strengths of up to 20,000 psi (140 Mpa) have been used in differentapplications. Laboratories have produced strengths approaching 60,000 psi (480 Mpa) at 28 days for high strength concrete.High-strength concrete can resist loads that normal-strength concrete cannot. Several distinctadvantages and disadvantagescan be analysed. It is important to consider all peripheral results of selecting high-strength concrete since special considerations must be addressed beyond strength properties.Once it is decided to use high-strength, high-performance concrete, themix design and production processcan begin. The materials used and concepts involved in increasing the strength of concrete must be clearly understood in order to obtain the desired properties. Testing is an integral step in the production process, since quality con trol studies show that slight changes in mixture proportions can lead to large changes in the compressive strength of concrete. When the design proportioning is complete, mixing can commence with extra consideration forworkability and related propertiesof the mix.The primary difference between high-strength concrete and normal-strength concrete relates to the compressive strength that refers to the maximum resistance of a concrete sample to applied pressure. Although there is no precise point of separation between high-strength concrete and normal-strength concrete, theAmerican Concrete Institutedefines high-strength concrete as concrete with a compressive strength greater than 6,000 psi. Manufacture of high-strength concrete involves making optimal use of the basic ingredients that constitute normal-strength concrete. Producers of high-strength concrete know what factors affect compressive strength and know h ow to manipulate those factors to achieve the required strength. In addition to selecting a high-quality Portland cement, producers optimize aggregates, then optimize the combination of materials by varying the proportions of cement, water, aggregates, and admixtures.When selecting aggregates for high-strength concrete, producers consider the strength of the aggregate, the optimum size of the aggregate, the bond between the cement paste and the aggregate, and the surface characteristics of the aggregate. Any of these properties could limit the ultimate strength of high-strength concrete.Materials for High Strength ConcreteCementCement composition and fineness play an important role in achieving high strength of concrete. It is also required that the cement is compatible with chemical admixtures to obtain the high-strength. Experience has shown that low-C3A cements generally produce concrete with improved rheology (high strength).AggregateSelection of right aggregates plays an import ant role for the design of high-strength concrete mix. The low-water to cement ratio used in high-strength concrete makes the concrete denser and the aggregate may become the weak link in the development of the mechanical strength. Extreme care is necessary, therefore, in the selection of aggregate to be used in very high-strength concrete. The particle size distribution of the fine aggregates plays an important role in the high strength concrete. The particle size distribution of fine aggregate that meets the ASTM specifications is adequate for high-strength concrete mixtures. The recommended fine modulus of aggregate for high strength concrete is around 3.0 due to the following reasons: * High-strength concrete mixtures already have large amounts of small particles of cement and pozzolan, therefore fine particles of aggregate will not improve the workability of the mix; * The use of coarser fine aggregates requires less water to obtain the same workability; and * During the mixing process, the coarser fine aggregates will generate higher shearing stresses that can help prevent flocculation of the cement paste.Guidelines for the selection of materials * For the higher target compressive strength of concrete, the maximum size of concrete selected should be small, so that the concrete can become denser and compacted with less void ratio. * Up to 70 MPa compressive strength can be produced with a good coarse aggregate of a maximum size ranging from 20 to 28 mm. * To produce 100 MPa compressive strength aggregate with a maximum size of 10 to 20 mm should be used. * To date, concretes with compressive strengths of over 125 MPa have been produced, with 10 to 14 mm maximum size coarse aggregate. * While silica fume is usually not really necessary for compressive strengths under 70 MPa, most concrete mixtures contain it when higher strengths are specified.Differences between Normal Strength Concrete and High Strength Concrete * Micro-cracks are developed in the norma l strength concrete when its compressive strength reaches 40% of the strength. The cracks interconnect when the stress reaches 80-90% of the strength (NSC). This is not applicable to the high strength concrete (HSC). * The fracture surface in NSC is rough. The fracture develops along the transition zone between the matrix and aggregates. Fewer aggregate particles are broken. The fracture surface in HSC is smooth. The cracks move without discontinuities between the matrix and aggregates. * High strength concrete and high-performance concrete are not synonymous because strength and performance of concrete are different properties of concrete. High-strength concrete is defined based on its compressive strength at a given age. * During 1970s, any concrete mixtures which showed 40 MPa or more compressive strength at 28 days were designated as high strength concrete. As the time passed, more and more high strength concrete such as 60 100 MPa, were developed which were used for the constr uction of long-span bridges, skyscrapers etc. The strength of high performance concrete may not be more than 25 MPa at 28 days. * While high strength concreteis defined purely on the basis of its compressive strength, high-performance concrete (HPC)is defined as concrete mixtures possessing high workability, high durability and high ultimate strength at 28 days. It is also a concretethat meets special combinations of performance and uniformity requirements that cannot always be achieved routinely using conventional constituents and normal mixing, placing, and curing practice.Main Ingredient of High Strength ConcretePozzolans, such as fly ash and silica fume, are the most commonly used mineral admixtures in high-strength concrete. These materials impart additional strength to the concrete by reacting with Portland cement hydration products to create additional C-S-H gel, the part of the paste responsible for concrete strength.It would be difficult to produce high-strength concrete mi xtures without using chemical admixtures. A common practice is to use a superplasticizer in combination with a water-reducing retarder. The superplasticizer gives the concrete adequate workability at low water-cement ratios, leading to concrete with greater strength. The water-reducing retarder slows the hydration of the cement and allows workers more time to place the concrete.High-strength concrete is specified where reduced weight is important or where architectural considerations call for small support elements. By carrying loads more efficiently than normal-strength concrete, high-strength concrete also reduces the total amount of material placed and lowers the overall cost of the structure.The most common use of high-strength concrete is for construction of high-rise buildings. At 969 feet, Chicago's 311 South Wacker Drive uses concrete with compressive strengths up to 12,000 psi and is one of the tallest concrete buildings in the United States.High strength concrete can also be achieved by reducing porosity, in-homogeneity, and micro-cracks in the hydrated cement paste and the transition zone. Consequently, there is a reduction of the thickness of the interfacial transition zone in high-strength concrete. The densification of the interfacial transition zone allows for efficient load transfer between the cement mortar and the coarse aggregate, contributing to the strength of the concrete.High Density ConcreteHigh density concreteis a concrete having a density in the range of 6000 to 6400 kg.High density concrete is also known asHeavy weight concrete.High density concreteis mainly used for the purpose of radiation shielding, for counterweights and other uses where high density is required. Thehigh density concretehas a better shielding...

Importance Of Efficient Territory Management In Distribution Planning Finance Essay - Free Essay Example

Sample details Pages: 7 Words: 2034 Downloads: 2 Date added: 2017/06/26 Category Finance Essay Type Argumentative essay Did you like this example? The current paper is a theoretical approach to the management of territories according to sales force, which has an important role in the realization of distribution. The central element is the way in which agents split their efforts between the activities and routes they are responsible with. A related issue is that of establishing what comes first defining the sales territory or performing the selling. The effects of the interaction between the number of distribution representatives and the delimiting of the territory they cover influence the measurement of the individual elements that contribute to achieving commercial performance. The basic elements of territory delimitation Commercial territories are delimited in order to help agents sell more efficiently. Delimitation is done by allocating a number of existing and potential clients to each distribution representative (DR) acting in a given area, usually, but not always, established on geographical criteria. The reasons for territory delimitation and the criteria according to which this is done may vary a lot from one case to another. Division into commercial territories is not required or useful in all situations. Reasons against these delimitations may occur when it comes to selling to friends or social contacts, or selling with the help of references received from other existing clients, as is the case of insurance or financial investment companies. Another reason against the existence of territories could also be the small size of the market, the reduced number of clients or DR, which does not justify such a division. Where information about potential clients or concerning the way in which a product would be received is not easily available, managers should leave the demarcation of territories for when these aspects will have been clarified. Don’t waste time! Our writers will create an original "Importance Of Efficient Territory Management In Distribution Planning Finance Essay" essay for you Create order The companies establish commercial territories out of the following reasons: To cover the whole market. Territories allow for the identification of existing or potential clients in a given area, reducing thus the likelihood of omitting some business opportunity or the overlapping of contacts and, therefore, helping to avoid excessive transport costs. To define the responsibilities of each DR more accurately. This delimitation allows an easier classification of accounts by name, number and frequency of contacts. To better adjust the selling activity to the clients needs. This is possible due to various reasons related to the respective location, such as knowledge of the local conditions and customs. Once more, similarity between distribution representatives and their potential clients may prove to be highly significant. To improve customer relations. The distribution representatives in a given area may find out more about their clients and establish a closer relation with them, visiting them regularly, a thing which represents, by itself, a time-saving source. But excessive contacts and wasting time with too many courtesy visits should be avoided. To reduce distribution expenses. The number of travels and the related costs are much more reduced if they are situated within the same area. For this reason, most of the companies insist that their distribution representatives should live in the area they cover. As means of facilitating performance evaluation. Commercial situations related to previous periods, to a plan or to some measure of the potential are easier to work out and more accurate when they refer to a well-defined territory. Sales managers can also draw comparisons between territories which could help them realize how to improve the activity of the entire sales personnel. To help the distribution representatives work. Demarcating territories supports a better coordination among the different departments of a company, between the concrete marketing and advertising activities undertaken by it, at the same time contributing to sustaining and motivating distribution representatives who thus become managers of the areas they cover. The most convincing reason is that territorial delimitation facilitates the implementation of the concept of marketing, contributing to a better identification of the clients needs and allowing for more specific actions with a view to satisfying them. In the environment in which selling and distribution take place nowadays, the ability to conduct an efficient management of territories is becoming increasingly important, this being the prerequisite for achieving optimum distribution in terms of costs. The widely accepted procedure for establishing commercial territories covers the following five phases: Phase I: Choosing the fundamental unit To better define territories, one chooses a starting point that relies on different preexisting divisions, such as economic regions. The differing population density, income differences and industrial particularities make these divisions unequal in terms of their commercial potential. Where possible, it is recommended that a smaller starting unit be established, because larger commercial areas may be subsequently created by merging several of these divisions. The market features, the distribution systems and the company reputation are factors of greater influence than the simple geographical borders. Phase II: Evaluation of accounts and commercial potential The data systems concerning markets may provide all the information required to make decisions in this respect. In the cases where exact information may be obtained about the market and clients, territory organization can be relatively easy. This involves the classification of all potential clients into different categories, such as yet unverified tracks, existing, past or future clients. The advantages of using computerized systems materialize into the ability of quickly selecting potential accounts according to a series of relevant features. Computers can also be used in storing information about the status of the accounts, their real and potential value. The majority of companies divide their accounts according to a classification of the ABC type: A = highly important accounts, B = average importance accounts, C = less important accounts. Phase III: The analysis of distribution representatives workload The agents workload is an estimate of the time and efforts required to cover the assigned geographical territory. This approximation contains the number of accounts of different types, the frequency of contacts, the time allotted to each of them, the time needed to travel among contacts, as well as the time spend with non-commercial activities. The difficulties which may arise when calculating the value of the workload include: Type of product. Fast-moving consumer goods require less explanations or demonstrations than technological products. The activity in this field is carried out recurrently, according to some well-established, almost routine patterns. There are, however, certain industrial or other special goods whose benefits require a more detailed presentation, making such visits take longer. Type of sales. Distribution representatives may deal with developing and consolidating an account which may take them more time than servicing the existing accounts. They can be faced with having to contact several persons within the same account whereas, in the other cases, they only have to meet with the actual customer. Certain types of sales require some missionary or development activity, while others may need a larger-scale promotional activity. The novelty of the products or of the market. In the case of developing products or markets, it is expected that there should be a need of longer time for each visit and less sales for each account than in the case of existing products or accounts. Accounts take time to develop and a large number of accounts means a greater workload in a developing area than is needed for achieving the same volume of sales in a well-established territory. The market share, the position and the competitive advantage of the company in the respective area. If competitors are already well positioned on the respective market, the work of distribution representatives to maintain each account will be far more difficult and will usually require more time. Most companies have a larger market share at home, that is why the task of distribution representatives is substantially more difficult when they have to work in regions away from the companys headquarters. It may happen that some agents obtain better results even in such circumstances, but this may be given rather by a greater efficiency of the distributors in the respective area than their own dealer qualities. Phase IV: Delimitation of basic territorial units The objective of this phase is to determine the commercial potential of the distribution representative assigned for a given area. This potential is, in its turn, related to the objectives of the sales staff. As in the case of sales forecasts, there are two distinct methods which may be used: the method of calculation by accumulation and the method of decomposition. The procedure is as follows: The number, size and location of customers are established, also taking into consideration their current, past and potential accounts. These accounts can be classified and grouped properly, for example according to size or other criteria. The number of contacts needed for each account, the time and frequency of visits are determined. A calculation is made concerning how many accounts each DR can serve. It is useful to use an ABC classification. Specifically, there will be an average of contacts that have to be made daily, the average frequency for each account and the average time for selling in each case. The demarcation lines are drawn, taking into consideration a realistic amount of work which should be commensurate with the basic geographical unit. The method of calculation by accumulation can be applied with the help of a computerized system. Information about each buyer resulted from the data collected during contacts may be used to maintain a file with information about clients (Vavra, 1992). Such hypotheses are more difficult to sustain in practice. Or, on the contrary, managers may adopt the method of decomposition in territory planning: starting from a nationwide estimate of the market potential and market share, one may approximate the sales potential; this estimate is then divided by the number of people available (or which can be recruited); finally, realistic geographical boundaries are drawn. The disadvantage of this method is that by trying to equalize the territories commercial potential, a difference in workloads occurs which makes geographical borders unrealistic. This issue is further strengthened by the variations in market conditions and the fluctuating efficiency of distributors, so that this quite simplistic method turns out to be, in fact, quite complicated. Phase V: Assigning distribution representatives to territories After establishing the territories, these must be individually assigned to distribution representatives. These may differ in knowledge level, skill and ability, which makes some be more efficient than others. Practice has shown how important it is to find distribution representatives that match the customers but beside this, there are still other factors which allow them to be efficient. The managers responsibility is to put these variables in order of priority, trying at least to improve the situation of each of them if not to find the best solution. Differences in skill, as well as the agents desire or inclination to deal with other areas than the ones they have been assigned to may require the use of compromise which, although not optimal, is still applicable. Time management Most improvements in this respect may be achieved by agents themselves through more discipline and increased professionalism. Among possible improvements, we may mention: The work day should start earlier and end later; Less discussions; Less breaks; Less protocol actions. Efficient time management means: Better work planning; Less visits to undecided or unimportant clients; Better use of travel and waiting time; An increased use of the phone, including for establishing the meeting list. Factors which distribution representatives should take into consideration when managing their duty hours include: Time for elaborating official documents; Duration of each visit; Travel duration; Number of visits; Order of visits; Time given to developing new relations; Time taken by non-commercial activities; Time wasted in making conversations with clients. As recommended as it might be to allow each DR to manage time on ones own, managers have the obligation not only to monitor, but also to stop the incorrect use of time and to promote more efficient practices for making sales. Conclusions An optimal territorial demarcation has the following features: areas are easy to administer; sales potential is relatively easy to estimate; time needed to travel and related costs are reduced to the minimum; there is a homogeneous distribution of opportunities to sell products among existing and potential customers; workloads are equalized. The most important factors to be taken into consideration when establishing territories are the market potential and the density and dispersion of accounts.

The Goal A Process Of Ongoing Improvement - 1468 Words

Patricia Reyes MAN4504 - P80 April 27, 2016 â€Å"The Goal: A Process of Ongoing Improvement† After reading the goal I can say that Eliyahu Goldratt is one of the most important and influential people in the business world. The Goal is special because it explains in detail a business model through a fiction novel. The drama of Alex, the main character of the story, is developed all throughout the book as his many marital problems increase because of all the time he spends at the plant and ignores his family. Alex comes to a balance between his family life and his career, but only after spending a lot of time analyzing and reconsidering many business processes within his plant. In this essay, I summarize Goldratt’s The Goal: A Process of†¦show more content†¦Although the reader is never told what kind of product the is manufactured in this company, later on you learn that they use heavy machinery and elaborate engineering processes to manufacture their products. Since Alex’s plant has not been profitable for quite some time, the division president comes in one day and informs Alex that the plant will be closing down within 3 months unless he is able to make significant improvements. Alex does not wish to give up all his hard work for so many years and starts to think about ways to improve the plant and save it from being closed down. The first thing that comes to his mind is to speak to his former professor, Jonah. For my surprise, Jonah is a physicist, but the Alex calls him because he remembered a meeting with him a few months ago during which Jonah puts in question Alex’s business decisions. When Alex is asked to give a presentation at a UniWare division meeting, Jonah raises particular questions about the way Alex defines what is productivity and efficiency in his presentation. However, Alex gets upset about this claiming that he has an MBA, and Jonah is â€Å"just† a scientist. What Alex did not know is that Jonah has been an independent consultant working to help businesses improve their productivity and efficiency. Jonah is a very busy man, constantly traveling; and during many phone conversations and face-to-face meetings, he explained his business model to

Achilles Vs Agamemnon Essay Example For Students

Achilles Vs Agamemnon Essay A monologue from the play by Seneca NOTE: This monologue is reprinted from Senecas Tragedy, v. ii. Trans. Frank Justus Miller. New York: G.P. Putnams Sons, 1917. CASSANDRA: Where am I? Fled is the kindly light, deep darkness blinds my eyes, and the sky, buried in gloom, is hidden away. But see! with double sun the day gleams forth, and double Argos lifts up twin palaces! Idas groves I see; there sits the shepherd, fateful judge midst mighty goddesses. Fear him, ye kings, I warn you, fear the child of stolen love; that rustic foundling shall overturn your house. What means that mad woman with drawn sword in hand? What hero seeks she with her right hand, a Spartan in her garb, but carrying an Amazonian axe? What sight is that other which now employs mine eyes? The king of beasts with his proud neck, by a base fang lies low, an Afric lion, suffering the bloody bites of his bold lioness. Why do ye summon me, saved only of my house, my kindred shades? Thee, father, do I follow, eye-witness of Troys burial; thee, brother, help of the Phrygians, terror of the Greeks, I see not in thine old-time splendour, or with thine hands hot from the burning of the ships, but mangled of limb, with those arms wounded by the deep-sunk thongs; thee, Troilus, I follow, too early with Achilles met; unrecognizable the face thou wearest, Deiphobus, the gift of thy new wife. Tis sweet to fare along the very Stygian pools; sweet to behold Tartarus savage dog and the realms of greedy Dis! To-day this skiff of murky Phlegethon shall bear royal souls, vanquished and vanquisher. Ye shades, I pray; thou stream on which the gods make oath, thee no less I pray: for a little withdrawn the covering of that dark world, that on Mycenae the shadowy throng of Phrygians may look forth. Behold, poor souls; the fates turn backward on themselves. They press on, the squalid sisters, their bloody lashes brandishing; their left hands half-burned torches bear; bloated are their pallid cheeks, and dusky robes of death their hollow loins encircle; the fearsome cries of night resound, and a huge bodys bones, rotting with long decay, lie in a slimy marsh. And see! that spe nt old man, forgetting thirst, no longer catches at the mocking waters, grieving at death to come; but father Dardanus exults and walks along with stately tread.