Asphalt known as bitumen, is a sticky and viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, is classed as a pitch. Before the 20th century, the term asphaltum was used; the word is derived from the Ancient Greek ἄσφαλτος ásphaltos. The primary use of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete, its other main uses are for bituminous waterproofing products, including production of roofing felt and for sealing flat roofs. The terms "asphalt" and "bitumen" are used interchangeably to mean both natural and manufactured forms of the substance. In American English, "asphalt" is used for a refined residue from the distillation process of selected crude oils. Outside the United States, the product is called "bitumen", geologists worldwide prefer the term for the occurring variety. Common colloquial usage refers to various forms of asphalt as "tar", as in the name of the La Brea Tar Pits.
Occurring asphalt is sometimes specified by the term "crude bitumen". Its viscosity is similar to that of cold molasses while the material obtained from the fractional distillation of crude oil boiling at 525 °C is sometimes referred to as "refined bitumen"; the Canadian province of Alberta has most of the world's reserves of natural asphalt in the Athabasca oil sands, which cover 142,000 square kilometres, an area larger than England. The word "asphalt" is derived from the late Middle English, in turn from French asphalte, based on Late Latin asphalton, the latinisation of the Greek ἄσφαλτος, a word meaning "asphalt/bitumen/pitch", which derives from ἀ-, "without" and σφάλλω, "make fall"; the first use of asphalt by the ancients was in the nature of a cement for securing or joining together various objects, it thus seems that the name itself was expressive of this application. Herodotus mentioned that bitumen was brought to Babylon to build its gigantic fortification wall. From the Greek, the word passed into late Latin, thence into French and English.
In French, the term asphalte is used for occurring asphalt-soaked limestone deposits, for specialised manufactured products with fewer voids or greater bitumen content than the "asphaltic concrete" used to pave roads. The expression "bitumen" originated in the Sanskrit words jatu, meaning "pitch", jatu-krit, meaning "pitch creating" or "pitch producing"; the Latin equivalent is claimed by some to be gwitu-men, by others, subsequently shortened to bitumen, thence passing via French into English. From the same root is derived the Anglo-Saxon word cwidu, the German word Kitt and the old Norse word kvada. In British English, "bitumen" is used instead of "asphalt"; the word "asphalt" is instead used to refer to asphalt concrete, a mixture of construction aggregate and asphalt itself. Bitumen mixed with clay was called "asphaltum", but the term is less used today. In Australian English, the word "asphalt" is used to describe a mix of construction aggregate. "Bitumen" refers to the liquid derived from the heavy-residues from crude oil distillation.
In American English, "asphalt" is equivalent to the British "bitumen". However, "asphalt" is commonly used as a shortened form of "asphalt concrete". In Canadian English, the word "bitumen" is used to refer to the vast Canadian deposits of heavy crude oil, while "asphalt" is used for the oil refinery product. Diluted bitumen is known as "dilbit" in the Canadian petroleum industry, while bitumen "upgraded" to synthetic crude oil is known as "syncrude", syncrude blended with bitumen is called "synbit"."Bitumen" is still the preferred geological term for occurring deposits of the solid or semi-solid form of petroleum. "Bituminous rock" is a form of sandstone impregnated with bitumen. The oil sands of Alberta, Canada are a similar material. Neither of the terms "asphalt" or "bitumen" should be confused with coal tars. Tar is the thick liquid product of the dry distillation and pyrolysis of organic hydrocarbons sourced from vegetation masses, whether fossilized as with coal, or freshly harvested; the majority of bitumen, on the other hand, was formed when vast quantities of organic animal materials were deposited by water and buried hundreds of metres deep at the diagenetic point, where the disorganized fatty hydrocarbon molecules joined together in long chains in the absence of oxygen.
Bitumen occurs as a solid or viscous liquid. It may be mixed in with coal deposits. Bitumen, coal using the Bergius process, can be refined into petrols such as gasoline, bitumen may be distilled into tar, not the other way around; the components of asphalt include four main classes of compounds: Naphthene aromatics, consisting of hydrogenated polycyclic aromatic compounds Polar aromatics, consisting of high molecular weight phenols and carboxylic acids produced by partial oxidation of the material Saturated hydrocarbons. Most natural bitumens a
National Academies of Sciences, Engineering, and Medicine
The National Academies of Sciences and Medicine is the collective scientific national academy of the United States. The name is used interchangeably in two senses: as an umbrella term for its three quasi-independent honorific member organizations, and as the brand for studies and reports issued by the operating arm of the three academies, the National Research Council. The NRC was first formed in 1916 as an activity of the NAS. Now jointly governed by all three academies, it produces some 200 publications annually which are published by the National Academies Press; the US National Academy of Sciences was created by an Act of Incorporation dated March 3, 1863, signed by President of the United States Abraham Lincoln The Act stated that "... the Academy shall, whenever called upon by any department of the Government, examine and report upon any subject of science or art.... " With the American civil war raging, the new Academy was presented with few problems to solve, but it did address matters of "... coinage and measures, iron ship hulls, the purity of whiskey..."
All subsequently affiliated organizations have been created under this same overall congressional charter, including the two younger academies, National Academy of Engineering and NAM. Under this same charter, the National Research Council was created in 1916. On June 19 of that year US President Woodrow Wilson requested that the National Academy of Sciences organize a "National Research Council"; the purpose of the Council was in part to foster and encourage "the increased use of scientific research in the development of American industries... the employment of scientific methods in strengthening the national defense... and such other applications of science as will promote the national security and welfare."At the time, the Academy's effort to support national defense readiness, the Committee on Nitric Acid Supply, was approved by Secretary of War Newton D. Baker. Nitric acid was the substance basic in the making of propellants such as cordite, high explosives, dyes and other products but availability was limited due to World War I.
The NRC, through its committee, recommended importing Chilean saltpeter and the construction of four new ordinance plants. These recommendations were accepted by the War Department in June 1917, although the plants were not completed prior to the end of the war. In 1918, Wilson formalized the NRC's existence under Executive Order 2859. Wilson's order declared the function of the NRC to be in general: "o stimulate research in the mathematical. Physical, biological sciences, and in the application of these sciences to engineering, agriculture. Medicine, and other useful arts. With the object of increasing knowledge, of strengthening the national defense, of contributing in other ways to the public welfare."During World War I, the United States was at war, the NRC operated as the Department of Science and Research of the Council of National Defense as well as the Science and Research Division of the United States Army Signal Corps. When war was first declared, the Council had organized committees on gas warfare.
On June 1, 1917, the council convened a meeting of scientific representatives of the United Kingdom and France with interested parties from the U. S. on the subject of submarine detection. Another meeting with the British and French was held in Paris in October 1918, at which more details of their work was disclosed; as a result of these meetings, the NRC recommended that scientists be brought together to work on the problems associated with submarine detection. Due to the success of council-directed research in producing a sound-based method of detecting submarines, as well as other military innovations, the NRC was retained at the end of the war, though it was decoupled from the military. NRC's Articles of Organization have been changed only three times: in 1956, January 1993, July 2015; the National Academy of Sciences, National Academy of Engineering and National Academy of Medicine are honorary membership organizations, each of which has its own governing Council, each of which elects its own new members.
The membership of the three academies totals more than 6,300 scientists and health professionals. New members for each organization are elected annually by current members, based on their distinguished and continuing achievements in original research. By the terms of the original 1863 Congressional charter, the three academies serve pro bono as "advisers to the nation on science and medicine." The program units known as the National Research Council, are collectively the operating arm of the three academies for the purpose of providing objective policy advice. Although separately chartered, it falls under the overall charter of the National Academy of Sciences, whose ultimate fiduciary body is the NAS Council. In actual practice, the NAS Council delegates governing authority to a Governing Board of the National Research Council, chaired jointly by the presidents of the three academies, with additional members chosen by them or specified in the charters of the academies. Under this three-academy umbrella, the program units produce reports that shape policies, inform public opinion, advance the pursuit of science and medicine.
There are seven major divisions: Division of Behavioral and Social Sciences and Education, Division of E
Federal Highway Administration
The Federal Highway Administration is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program and the Federal Lands Highway Program, its role had been performed by the Office of Road Inquiry, Office of Public Roads and the Bureau of Public Roads. The organization has a complicated history; the Office of Road Inquiry was founded in 1893. In 1905 that organization's name was changed to the Office of Public Roads which became a division of the United States Department of Agriculture; the name was changed again to the Bureau of Public Roads in 1915 and to the Public Roads Administration in 1939. It was shifted to the Federal Works Agency, abolished in 1949 when its name reverted to Bureau of Public Roads under the Department of Commerce. With the coming of the bicycle in the 1890s, interest grew regarding the improvement of streets and roads in America; the traditional method of putting the burden on maintaining roads on local landowners was inadequate.
New York State took the lead in 1898, by 1916 the old system had been discarded everywhere area. Demands grew for local and state government to take charge. With the coming of the automobile after 1910, urgent efforts were made to upgrade and modernize dirt roads designed for horse-drawn wagon traffic; the American Association for Highway Improvement was organized in 1910. Funding came from automobile registration, taxes on motor fuels, as well as state aid. In 1916, federal-aid was first made available to improve post-roads, promote general commerce. Congress appropriated $75 million over a five-year period, with the Secretary of Agriculture in charge through the Bureau of Public Roads, in cooperation with the state highway departments. There were 2.4 million miles of rural dirt rural roads in 1914. The increasing speed of automobiles, trucks, made maintenance and repair high-priority item. Concrete was first used in 1893, expanded until it became the dominant surfacing material in the 1930s. Federal aid began in 1917.
From 1917 through 1941, 261,000 miles of highways were built with federal aid, cost $5.31 billion. Federal funds totaled $3.17 billion, state-local funds were $2.14 billion. The FHWA was created on October 15, 1966. In 1967 the functions of the Bureau of Public Roads were transferred to the new organization, it was one of three original bureaus along with the'Bureau of Motor Carrier Safety' and the'National Highway Safety Bureau'. The FHWA’s role in the Federal-aid Highway Program is to oversee federal funds used for constructing and maintaining the National Highway System; this funding comes from the federal gasoline tax and goes to state departments of transportation. FHWA oversees projects using these funds to ensure that federal requirements for project eligibility, contract administration and construction standards are adhered to. Under the Federal Lands Highway Program, the FHWA provides highway design and construction services for various federal land-management agencies, such as the Forest Service and the National Park Service.
In addition to these programs, the FHWA performs and sponsors research in the areas of roadway safety, highway materials and construction methods, provides funding to local technical assistance program centers to disseminate research results to local highway agencies. The FHWA publishes the “Manual on Uniform Traffic Control Devices”, used by most highway agencies in the United States; the MUTCD specifies such things as the size and height of traffic signs, traffic signals and road surface markings. The Federal Highway Administration is overseen by an Administrator appointed by the President of the United States by and with the consent of the United States Senate; the Administrator works under the direction of the Secretary of Transportation and Deputy Secretary of Transportation. The internal organization of the FHWA is as follows: Administrator Executive Director Office of Infrastructure Office of Research and Technology Public Roads magazine Office of Planning and Realty Office of Policy and Government Affairs Office of the Chief Financial Officer Office of Administration Office of Operations Office of Safety Office of Federal Lands Highway Office of Chief Counsel Office of Civil Rights Office of Public Affairs Long-Term Pavement Performance is a program supported by FHWA to collect and analyse road data.
The LTPP program was initiated by the Transportation Research Board of the National Research Council in the early 1980s. Federal Highway Administration with the cooperation of the American Association of State Highway and Transportation Officials sponsored the program; as a result of this program, FHWA has collected a huge database of road performance. FHWA and ASCE hold an annual contest known as LTPP International Data Analysis Contest, based on challenging researchers to answer a question based on the LTPP data. Current: Administrator: Brandye Hendrickson Deputy Administrator: Brandye Hendrickson Executive Director: Thomas Everett Alph Bartelsmeyer August 10, 1970- January 25, 1974 Alinda Burke - January 1, 1980 -? J. Richard Capka August 5, 2002 - May 31, 2006 Gregory G. Nadeau July 8, 2009 – July 30, 2014 Brandye Hendrickson July 24, 2017 - Present Federal Motor Carrier Safety Administration Hi
American Society of Civil Engineers
The American Society of Civil Engineers is a tax-exempt professional body founded in 1852 to represent members of the civil engineering profession worldwide. Headquartered in Reston, Virginia, it is the oldest national engineering society in the United States, its constitution was based on the older Boston Society of Civil Engineers from 1848. The American Society of Civil Engineers represents more than 150,000 members of the civil engineering profession in 177 countries. Through the expertise of its active membership, ASCE is a leading provider of technical and professional conferences and continuing education, the world’s largest publisher of civil engineering content, an authoritative source for codes and standards that protect the public. ASCE stands for the "American Society of Civil Engineers"; the society was chartered under this full legal name when it was incorporated on April 17, 1877 in New York state. ASCE's membership has long been composed of civil engineers and affiliate members who are not students or classically trained engineers or scientists.
ASCE is dedicated to the "...advancement of the science and profession of Civil engineering and the enhancement of human welfare through the activities of society members." It has about 152,000 members in about 177 countries. Its mission is to provide essential value to "...members, their careers, our partners, the public...... Facilitate the advancement of technology; the first serious and documented attempts to organize civil engineers as a professional society in the newly created United States were in the early 19th century. In 1828, John Kilbourn of Ohio, managed a short-lived "Civil Engineering Journal", editorializing about the recent incorporation of the Institution of Civil Engineers in Great Britain that same year, Kilbourn suggested that the American corps of engineers could constitute an American society of civil engineers. In 1834, an American trade periodical, the "American Railroad Journal" advocated for similar national organization of civil engineers. On December 17, 1838, a petition started circulating asking civil engineers to meet in 1839 in Baltimore, Maryland to organize a permanent society of civil engineers.
Prior to that, thirteen notable civil engineers identifiable as being from New York, Pennsylvania, or Maryland met in Philadelphia. This group presented the Franklin Institute of Philadelphia with a formal proposal that an Institution of American Civil Engineers be established as an adjunct of the Franklin..." Some of them were: Benjamin Wright. In 1969, the American Society of Civil Engineers declared Wright to be the'Father of American Civil Engineering'. William Strickland Pennsylvanians Solomon. W. Roberts, the latter being Chief Engineer for the Allegheny Portage railroad, the first crossing of the Allegheny mountains Forty engineers appeared at the February, 1839 meeting Baltimore including J. Edgar Thomson, Roberts, Edward Miller, the Maryland engineers Isaac Trimble and architect Benjamin H. Latrobe and attendees from as far as Massachusetts and Louisiana. Subsequently, a group met again in Philadelphia, led by its Secretary, Edward Miller to take steps to formalize the society, participants now included such other notable engineers as: John B.
Jervis Claudius Crozet William Gibbs McNeill George Washington Whistler Walter Gwynn J. Edgar Thompson Sylvester Welch, brother of future ASCE president Ashbel Welch Other members included Jonathan Knight and Moncure Robinson. Miller drafted up a proposed constitution which gave the society's purpose as "the collection and diffusion of professional knowledge, the advancement of mechanical philosophy, the elevation of the character and standing of the Civil Engineers of the United States." Membership in the new society restricted membership to engineers and "architects and eminent machinists were to be admitted only as Associates." The proposed constitution failed, no further attempts were made to form another society. Miller ascribed the failure due to the difficulties of assembling members due available means for traveling in the country at time. One of the other difficulties members would have to contend with was the requirement to produce each year, one unpublished paper or "...present a scientific book, plan or model, not in the possession of the Society, under the penalty of $10."
In that same period, the editor of the American Railroad Journal commented that effort had failed in part due to certain jealousies which arose due to the proposed affiliation with the Franklin Institute. That journal continued discussion on forming an engineers' organization from 1839 thru 1843 serving its own self interests in advocating its journal as a replacement for a professional society but to no avail. During the 1840s, professional organizations continued to organize in the United States; the organizers motives were to "... improve common standards, foster research, disseminate knowledge through meetings and publications." Unlike earlier associations such as the American Philosophical Society, these newer associations were not seeking to limit membership as much as pursue "... more specialized interests." Examples of this surge in new professional organizations in America were the American Statistical Association, American Ethnological Society, American Medical Association, American Association for the Advancement of Science, National Education Association.
During this same period of association incorporations on the 1840s, attempts were aga
A road surface or pavement is the durable surface material laid down on an area intended to sustain vehicular or foot traffic, such as a road or walkway. In the past, gravel road surfaces and granite setts were extensively used, but these surfaces have been replaced by asphalt or concrete laid on a compacted base course. Road surfaces are marked to guide traffic. Today, permeable paving methods are beginning to be used for low-impact walkways. Pavements are crucial to countries such as US and Canada, which depend on road transportation. Therefore, research projects such as Long-Term Pavement Performance are launched to optimize the life-cycle of different road surfaces. Asphalt, sometimes called flexible pavement due to the nature in which it distributes loads, has been used since the 1920s; the viscous nature of the bitumen binder allows asphalt concrete to sustain significant plastic deformation, although fatigue from repeated loading over time is the most common failure mechanism. Most asphalt surfaces are laid on a gravel base, at least as thick as the asphalt layer, although some'full depth' asphalt surfaces are laid directly on the native subgrade.
In areas with soft or expansive subgrades such as clay or peat, thick gravel bases or stabilization of the subgrade with Portland cement or lime may be required. Polypropylene and polyester geosynthetics have been used for this purpose and in some northern countries, a layer of polystyrene boards have been used to delay and minimize frost penetration into the subgrade. Depending on the temperature at which it is applied, asphalt is categorized as hot mix, warm mix, or cold mix. Hot mix asphalt is applied at temperatures over 300 °F with a free floating screed. Warm mix asphalt is applied at temperatures of 200–250 °F, resulting in reduced energy usage and emissions of volatile organic compounds. Cold mix asphalt is used on lower-volume rural roads, where hot mix asphalt would cool too much on the long trip from the asphalt plant to the construction site. An asphalt concrete surface will be constructed for high-volume primary highways having an average annual daily traffic load greater than 1200 vehicles per day.
Advantages of asphalt roadways include low noise low cost compared with other paving methods, perceived ease of repair. Disadvantages include less durability than other paving methods, less tensile strength than concrete, the tendency to become slick and soft in hot weather and a certain amount of hydrocarbon pollution to soil and groundwater or waterways. In the mid-1960s, rubberized asphalt was used for the first time, mixing crumb rubber from used tires with asphalt. While a potential use for tires that would otherwise fill landfills and present a fire hazard, rubberized asphalt has shown greater incidence of wear in freeze-thaw cycles in temperate zones due to non-homogeneous expansion and contraction with non-rubber components; the application of rubberized asphalt is more temperature-sensitive, in many locations can only be applied at certain times of the year. Study results of the long-term acoustic benefits of rubberized asphalt are inconclusive. Initial application of rubberized asphalt may provide 3–5 decibels reduction in tire-pavement source noise emissions.
Compared to traditional passive attenuating measures, rubberized asphalt provides shorter-lasting and lesser acoustic benefits at much greater expense. Concrete surfaces are created using a concrete mix of Portland cement, coarse aggregate and water. In all modern mixes there will be various admixtures added to increase workability, reduce the required amount of water, mitigate harmful chemical reactions and for other beneficial purposes. In many cases there will be Portland cement substitutes added, such as fly ash; this can improve its physical properties. The material is applied in a freshly mixed slurry, worked mechanically to compact the interior and force some of the cement slurry to the surface to produce a smoother, denser surface free from honeycombing; the water allows the mix to combine molecularly in a chemical reaction called hydration. Concrete surfaces have been refined into three common types: jointed plain, jointed reinforced and continuously reinforced; the one item that distinguishes each type is the jointing system used to control crack development.
One of the major advantages of concrete pavements is they are stronger and more durable than asphalt roadways. They can be grooved to provide a durable skid-resistant surface. A notable disadvantage is that they can have a higher initial cost, can be more time-consuming to construct; this cost can be offset through the long life cycle of the pavement. Concrete pavement can be maintained over time utilizing a series of methods known as concrete pavement restoration which include diamond grinding, dowel bar retrofits and crack sealing, cross-stitching, etc. Diamond grinding is useful in reducing noise and restoring skid resistance in older concrete pavement; the first street in the United States to be paved with concrete was Court Avenue in Bellefontaine, Ohio in 1893. The first mile of concrete pavement in the United States was on Woodward Avenue in Detroit, Michigan in 1909. Following these pioneering uses, the Lincoln Highway Association, established in October 1913 to oversee the creation of one of the United States' earliest east-west transcontinental
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar and non-specialty grout. It was developed from other types of hydraulic lime in England in the mid 19th century, originates from limestone, it is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, adding 2 to 3 percent of gypsum. Several types of Portland cement are available; the most common, called ordinary Portland cement, is grey, but white Portland cement is available. Its name is derived from its similarity to Portland stone, quarried on the Isle of Portland in Dorset, England, it was named by Joseph Aspdin who obtained a patent for it in 1824. However, his son William Aspdin is regarded as the inventor of "modern" Portland cement due to his developments in the 1840s. Portland cement is caustic, so it can cause chemical burns; the powder can cause irritation or, with severe exposure, lung cancer, can contain some hazardous components, such as crystalline silica and hexavalent chromium.
Environmental concerns are the high energy consumption required to mine and transport the cement, the related air pollution, including the release of greenhouse gases, dioxin, NOx, SO2, particulates. The production of Portland cement contributes to about 10% of world carbon dioxide emission. To meet the rising global population, the International Energy Agency estimated that the cement production is set to increase between 12 to 23% by 2050. There are several ongoing researches targeting a suitable replacement of Portland cement by supplementary cementitious materials; the low cost and widespread availability of the limestone and other naturally-occurring materials used in Portland cement make it one of the lowest-cost materials used over the last century. Concrete produced from Portland cement is one of the world's most versatile construction materials. Portland cement was developed from natural cements made in Britain beginning in the middle of the 18th century, its name is derived from its similarity to Portland stone, a type of building stone quarried on the Isle of Portland in Dorset, England.
The development of modern Portland cement began in 1756, when John Smeaton experimented with combinations of different limestones and additives, including trass and pozzolanas, relating to the planned construction of a lighthouse, now known as Smeaton's Tower. In the late 18th century, Roman cement was patented in 1796 by James Parker. Roman cement became popular, but was replaced by Portland cement in the 1850s. In 1811, James Frost produced a cement. James Frost is reported to have erected a manufactory for making of an artificial cement in 1826. In 1811 Edgar Dobbs of Southwark patented a cement of the kind invented 7 years by the French engineer Louis Vicat. Vicat's cement is an artificial hydraulic lime, is considered the'principal forerunner' of Portland cement; the name Portland cement is recorded in a directory published in 1823 being associated with a William Lockwood and others. In his 1824 cement patent, Joseph Aspdin called his invention "Portland cement" because of the its resemblance to Portland stone.
However, Aspdin's cement was nothing like modern Portland cement, but was a first step in the development of modern Portland cement, has been called a'proto-Portland cement'. William Aspdin had left his father's company. In the 1840's William Aspdin accidentally, produced calcium silicates which are a middle step in the development of Portland cement. In 1848, William Aspdin further improved his cement. In 1853, he moved to Germany, where he was involved in cement making. William Aspdin made what could be called'meso-Portland cement'. Isaac Charles Johnson further refined the production of'meso-Portland cement', claimed to be the real father of Portland cement. John Grant of the Metropolitan Board of Works in 1859 set out requirements for cement to be used in the London sewer project; this became a specification for Portland cement. The next development in the manufacture of Portland cement was the introduction of the rotary kiln, patented by Frederick Ransome in 1885 and 1886; the Hoffmann'endless' kiln, said to give'perfect control over combustion' was tested in 1860, showed the process produced a better grade of cement.
This cement was made at the Portland Cementfabrik Stern at Stettin, the first to use a Hoffmann kiln.. The Association of German Cement Manufacturers issued a standard on Portland cement in 1878. Portland cement had been imported into the United States from Germany and England, in the 1870s and 1880s, it was being produced by Eagle Portland cement near Kalamazoo, in 1875, the first Portland cement was produced in the Coplay Cement Company Kilns under the direction of David O. Saylor in Coplay, Pennsylvania. By the early 20th century, American-made Portland cement had displaced most of the imported Portland cement. ASTM C150 defines Portland cement as'hydraulic cement produced by pulverizing clinkers which consist of hydraulic calcium silicates containing one or more of the forms of calcium sulfate as an inter ground addition'; the European Standard EN 197-1 uses the following definition: Portland cement clinker is a hydraulic material which shall consist of at l