84-471: The Bellefontaine Examiner is a daily newspaper published at Bellefontaine , Ohio , United States . The newspaper covers international and national, regional and local topics, with a focus on stories affecting the surrounding Logan County . During an ice storm in 2005 that affected Logan County, the Bellefontaine Examiner was not published for several days; that point was the first time
168-412: A bitumen binder, which is frequently used for road surfaces , and polymer concretes that use polymers as a binder. Concrete is distinct from mortar . Whereas concrete is itself a building material, mortar is a bonding agent that typically holds bricks , tiles and other masonry units together. Grout is another material associated with concrete and cement. It does not contain coarse aggregates and
252-505: A Bellefontaine address. Several colleges and universities operate satellite campuses in the Bellefontaine area. These include: Bellefontaine has a public library, a branch of Logan County Libraries. The city is served by both print publishing and radio broadcasting. The Bellefontaine Examiner is the daily local newspaper. It is the latest in a series of newspapers which have been published in Bellefontaine since 1831. It has
336-455: A City Council meeting, prompting drag queens and supporters attending a later council meeting in support. In 2023, the opposing residents began pushing for a city ordinance that would classify drag performances as ‘adult entertainment,' making it one of the first municipalities in Ohio to do so. The Ohio Supreme Court unanimously ruled to remove the measure from the ballot when petitioners changed
420-433: A French structural and civil engineer . Concrete components or structures are compressed by tendon cables during, or after, their fabrication in order to strengthen them against tensile forces developing when put in service. Freyssinet patented the technique on 2 October 1928. Concrete is an artificial composite material , comprising a matrix of cementitious binder (typically Portland cement paste or asphalt ) and
504-452: A cementitious material forms a cement paste by the process of hydration. The cement paste glues the aggregate together, fills voids within it, and makes it flow more freely. As stated by Abrams' law , a lower water-to-cement ratio yields a stronger, more durable concrete, whereas more water gives a freer-flowing concrete with a higher slump . The hydration of cement involves many concurrent reactions. The process involves polymerization ,
588-400: A concrete component—and become a part of the binder for the aggregate. Fly ash and slag can enhance some properties of concrete such as fresh properties and durability. Alternatively, other materials can also be used as a concrete binder: the most prevalent substitute is asphalt , which is used as the binder in asphalt concrete . Admixtures are added to modify the cure rate or properties of
672-534: A current daily circulation of approximately 9500 copies. Operating currently are WPKO , an FM radio station, WPKO HD2, a second FM radio station, and its sister station WBLL , an AM radio station. These stations are owned and operated by V-Teck Communications. Two Christian radio stations WKEN , an FM radio station operating on FM frequency of 88.5 and WSOH , an FM radio station operating on FM frequency of 88.9. These stations are owned and operated by Soaring Eagle Promotions, Inc. Concrete Concrete
756-434: A dispersed phase or "filler" of aggregate (typically a rocky material, loose stones, and sand). The binder "glues" the filler together to form a synthetic conglomerate . Many types of concrete are available, determined by the formulations of binders and the types of aggregate used to suit the application of the engineered material. These variables determine strength and density, as well as chemical and thermal resistance of
840-452: A greater degree of fracture resistance even in seismically active environments. Roman concrete is significantly more resistant to erosion by seawater than modern concrete; it used pyroclastic materials which react with seawater to form Al- tobermorite crystals over time. The use of hot mixing and the presence of lime clasts are thought to give the concrete a self-healing ability, where cracks that form become filled with calcite that prevents
924-559: A key event in the history of architecture termed the Roman architectural revolution , freed Roman construction from the restrictions of stone and brick materials. It enabled revolutionary new designs in terms of both structural complexity and dimension. The Colosseum in Rome was built largely of concrete, and the Pantheon has the world's largest unreinforced concrete dome. Concrete, as
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#17328020782651008-415: A large aggregate that is too large for the size of the formwork, or which has too few smaller aggregate grades to serve to fill the gaps between the larger grades, or using too little or too much sand for the same reason, or using too little water, or too much cement, or even using jagged crushed stone instead of smoother round aggregate such as pebbles. Any combination of these factors and others may result in
1092-461: A large type of industrial facility called a concrete plant , or often a batch plant. The usual method of placement is casting in formwork , which holds the mix in shape until it has set enough to hold its shape unaided. Concrete plants come in two main types, ready-mix plants and central mix plants. A ready-mix plant blends all of the solid ingredients, while a central mix does the same but adds water. A central-mix plant offers more precise control of
1176-469: A mixture of calcium silicates ( alite , belite ), aluminates and ferrites —compounds, which will react with water. Portland cement and similar materials are made by heating limestone (a source of calcium) with clay or shale (a source of silicon, aluminium and iron) and grinding this product (called clinker ) with a source of sulfate (most commonly gypsum ). Cement kilns are extremely large, complex, and inherently dusty industrial installations. Of
1260-405: A number of manufactured aggregates, including air-cooled blast furnace slag and bottom ash are also permitted. The size distribution of the aggregate determines how much binder is required. Aggregate with a very even size distribution has the biggest gaps whereas adding aggregate with smaller particles tends to fill these gaps. The binder must fill the gaps between the aggregate as well as paste
1344-424: A semi-liquid slurry (paste) that can be shaped, typically by pouring it into a form. The concrete solidifies and hardens through a chemical process called hydration . The water reacts with the cement, which bonds the other components together, creating a robust, stone-like material. Other cementitious materials, such as fly ash and slag cement , are sometimes added—either pre-blended with the cement or directly as
1428-493: A simple, fast way of getting a basic idea of the properties of the finished concrete without having to perform testing in advance. Various governing bodies (such as British Standards ) define nominal mix ratios into a number of grades, usually ranging from lower compressive strength to higher compressive strength. The grades usually indicate the 28-day cure strength. Thorough mixing is essential to produce uniform, high-quality concrete. Separate paste mixing has shown that
1512-467: A small empire in the regions of southern Syria and northern Jordan from the 4th century BC. They discovered the advantages of hydraulic lime , with some self-cementing properties, by 700 BC. They built kilns to supply mortar for the construction of rubble masonry houses, concrete floors, and underground waterproof cisterns . They kept the cisterns secret as these enabled the Nabataeans to thrive in
1596-575: A statue of Bartholomew placed at its Main Street end; it became a pedestrian way. Since then one lane has been reopened for eastbound traffic. In 1979, Honda began manufacturing motorcycles in the nearby city of Marysville, Ohio . Since that time, Honda's operations in the Bellefontaine area have greatly expanded. Bellefontaine is a central location among Honda operations in Marysville, East Liberty , Russells Point , Anna , and Troy, Ohio . Honda
1680-399: Is Sandusky , with 79,555 residents. The Bellefontaine micropolis is not as populous as these, but does have a greater population than some micropolitan statistical areas traditionally considered to be small regional cities. (Examples: El Dorado, Arkansas ; Clovis, New Mexico ; and Red Wing, Minnesota .) Though official definitions of micropolitan statistical areas did not exist until 2003,
1764-484: Is exothermic , which means ambient temperature plays a significant role in how long it takes concrete to set. Often, additives (such as pozzolans or superplasticizers ) are included in the mixture to improve the physical properties of the wet mix, delay or accelerate the curing time, or otherwise change the finished material. Most concrete is poured with reinforcing materials (such as steel rebar ) embedded to provide tensile strength , yielding reinforced concrete . In
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#17328020782651848-406: Is Bellefontaine's largest employer in the early 21st century. U.S. Route 68 intersects with State Routes 47 and 540 in Bellefontaine. U.S. Route 33 , a freeway that has interchanges with US 68 and SR 540, skirts the northern edge of the city. To European settlers, Campbell Hill was first known as Hogue's Hill, perhaps a misspelling of Solomon Hoge's surname, the person who first deeded
1932-405: Is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water , and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminium combined. When aggregate is mixed with dry Portland cement and water ,
2016-535: Is a city in, and the county seat of, Logan County, Ohio , United States, located 48 miles (77 km) northwest of Columbus . The population was 14,115 at the 2020 census . It is the principal city of the Bellefontaine micropolitan area , which includes all of Logan County. The highest point in Ohio, Campbell Hill , is within the city limits. The name Bellefontaine means "beautiful spring" in French , and
2100-473: Is flat and had been covered with cement". "The floors were cement, in some places hard, but, by long exposure, broken, and now crumbling under the feet." "But throughout the wall was solid, and consisting of large stones imbedded in mortar, almost as hard as rock." Small-scale production of concrete-like materials was pioneered by the Nabatean traders who occupied and controlled a series of oases and developed
2184-612: Is purported to refer to several springs in the area. However, locally, the original French pronunciation is not used, and it is pronounced "bell fountain." Around 1777, the Shawnee war chief Blue Jacket ( Weyapiersenwah ) built a settlement here, known as "Blue Jacket's Town". Blue Jacket and his band had previously occupied a village along the Scioto River , but the American Revolutionary War had reached
2268-559: Is then blended with aggregates and any remaining batch water and final mixing is completed in conventional concrete mixing equipment. Workability is the ability of a fresh (plastic) concrete mix to fill the form/mold properly with the desired work (pouring, pumping, spreading, tamping, vibration) and without reducing the concrete's quality. Workability depends on water content, aggregate (shape and size distribution), cementitious content and age (level of hydration ) and can be modified by adding chemical admixtures, like superplasticizer. Raising
2352-519: Is too far south to experience lake effect snow from the Great Lakes region, however it does experience more snow than surrounding areas due to the city's elevation. Traditionally, Bellefontaine's elevation excludes it from tornadoes and floods that affect the majority of the Miami Valley . As of the census of 2000, there were 13,069 people, 5,319 households, and 3,436 families residing in
2436-566: Is usually either pourable or thixotropic , and is used to fill gaps between masonry components or coarse aggregate which has already been put in place. Some methods of concrete manufacture and repair involve pumping grout into the gaps to make up a solid mass in situ . The word concrete comes from the Latin word " concretus " (meaning compact or condensed), the perfect passive participle of " concrescere ", from " con -" (together) and " crescere " (to grow). Concrete floors were found in
2520-399: Is usually reinforced with materials that are strong in tension, typically steel rebar . The mix design depends on the type of structure being built, how the concrete is mixed and delivered, and how it is placed to form the structure. Portland cement is the most common type of cement in general usage. It is a basic ingredient of concrete, mortar , and many plasters . It consists of
2604-684: The Ohio Country . Blue Jacket and other American Indians who took up arms against the American revolutionaries relocated in order to be closer to their British allies at Detroit . After the United States gained independence, its forces continued warfare against former Indian allies of the British. Blue Jacket's Town was destroyed in Logan's Raid , conducted by Kentucky militia in 1786 at
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2688-532: The Ohio Hi-Point Career Center . In 2012 local real estate developer Small Nation purchased and renovated the former J.C. Penney building. Since then, the organization invested over $ 33 million in renovating over 56 downtown buildings and attracting new businesses to the area. The investment into the properties created roughly 200 jobs in the city. In 2018, Bellefontaine was classified as an Opportunity Zone to further attract investors to
2772-834: The Penn Central 's Indianapolis - Cleveland remnant of the Southwestern Limited, ended in 1971, upon Amtrak taking up private companies' long distance passenger operations. The Bellefontaine City Schools operate one elementary school , one intermediate school, one middle school , and one high school in the area. These schools have a combined enrollment of 2,840. In addition, the Ohio Hi-Point Career Center , located atop Campbell Hill, offers both secondary and post-secondary education. Enrolled at Ohio Hi-Point are 505 students. The neighboring Benjamin Logan Local School District campus also has
2856-480: The construction industry , whose demand is ever growing with greater impacts on raw material extraction, waste generation and landfill practices. Concrete production is the process of mixing together the various ingredients—water, aggregate, cement, and any additives—to produce concrete. Concrete production is time-sensitive. Once the ingredients are mixed, workers must put the concrete in place before it hardens. In modern usage, most concrete production takes place in
2940-627: The Mad River & Lake Erie Railroad built the first railroad to Bellefontaine. This began its reputation as a railroading town. In the 1890s the Cleveland, Cincinnati, Chicago and St. Louis Railway (also called the Big Four Railroad) built a main terminal in the city. This terminal boasted the largest roundhouse between New York and St. Louis . Though railroading hit hard times and the industry went through radical restructuring in
3024-508: The Romans knew it, was a new and revolutionary material. Laid in the shape of arches , vaults and domes , it quickly hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick. Modern tests show that opus caementicium had as much compressive strength as modern Portland-cement concrete (c. 200 kg/cm [20 MPa; 2,800 psi]). However, due to
3108-643: The absence of reinforcement, its tensile strength was far lower than modern reinforced concrete , and its mode of application also differed: Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice, often consisted of rubble . Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon
3192-428: The age of 18 living with them, 41.1% were married couples living together, 15.9% had a female householder with no husband present, 6.1% had a male householder with no wife present, and 36.8% were non-families. 30.6% of all households were made up of individuals, and 12.1% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 3.01. The median age in
3276-471: The area now constituting the Bellefontaine micropolis grew in population by 8.7 percent between 1990 and 2000. Bellefontaine has an elected mayor and city council style of government. Bellefontaine City Council Members serve 2 year terms. The city has 4 wards and 3 At-Large seats. The Logan County Historical Society and museum was first housed in the McBeth School, built in 1919 as the last of
3360-433: The area. Neighboring areas have begun using Bellefontaine as a model to attract more investment in their own towns. In 2022, Bellefontaine was named one of Ohio's Best Hometowns by Ohio Magazine for its downtown redevelopment efforts, thriving sense of community and appreciation for preserving local history. In 2022, Bellefontaine's Christmas parade included a drag queen and over 60 residents opposed their appearance at
3444-405: The average family size was 3.01. In the city the population was spread out, with 28.1% under the age of 18, 10.0% from 18 to 24, 29.1% from 25 to 44, 19.9% from 45 to 64, and 12.9% who were 65 years of age or older. The median age was 33 years. For every 100 females, there were 90.9 males. For every 100 females age 18 and over, there were 86.4 males. The median income for a household in the city
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3528-583: The ballot language after circulating petitions. According to the 2010 census, the city has a total area of 10.04 square miles (26.0 km ), all land. The city of Bellefontaine is at the convergence of the humid subtropical (Köppen Cfa ) and humid continental (Köppen Dfa ) climate zones according to the Köppen climate map. The region is characterized by four distinct seasons. Winters are cool to cold with mild periods, and summers are generally hot and muggy, with significant precipitation year-round. The city
3612-435: The cash-poor government granted tracts of land to veterans in payment for their services during the war. The Treaty of Greenville defined lands to be held by European Americans as separate from those to be held by natives but it was poorly administered in the area and whites frequently encroached on native lands. Bellefontaine was platted by European Americans in 1820 and incorporated by the legislature in 1835. In 1837,
3696-591: The city was 34.8 years. 27.1% of residents were under the age of 18; 9.1% were between the ages of 18 and 24; 26.3% were from 25 to 44; 24.7% were from 45 to 64; and 12.8% were 65 years of age or older. The gender makeup of the city was 48.4% male and 51.6% female. Bellefontaine is the center of the Bellefontaine Micropolitan Statistical Area , as defined by the U.S. Census Bureau. This micropolis consists solely of Logan County, Ohio . The 2000 census found 46,005 people in
3780-729: The city. Bellefontaine had been part of the New York Central Railroad 's St. Louis - Indianapolis - Cleveland corridor of passenger trains. Up to 1966, the New York Central ran the Southwestern Limited (St. Louis - New York City via Cleveland) through Bellefontaine. The city was also a crossing point for the New York Central's Detroit - Cincinnati trains. The last of these ( Ohio Special southbound, Michigan Special northbound) ended in 1958 or 1959. The final train running through Bellefontaine,
3864-429: The city. The population density was 1,491.3 inhabitants per square mile (575.8/km ). There were 5,722 housing units at an average density of 652.9 per square mile (252.1/km ). The racial makeup of the city was 90.82% White , 5.13% African American , 0.15% Native American , 0.93% Asian , 0.04% Pacific Islander , 0.53% from other races , and 2.40% from two or more races. Hispanic or Latino of any race were 1.12% of
3948-526: The concrete at the time of batching/mixing. (See § Production below.) The common types of admixtures are as follows: Inorganic materials that have pozzolanic or latent hydraulic properties, these very fine-grained materials are added to the concrete mix to improve the properties of concrete (mineral admixtures), or as a replacement for Portland cement (blended cements). Products which incorporate limestone , fly ash , blast furnace slag , and other useful materials with pozzolanic properties into
4032-399: The concrete can cause the initially placed material to begin to set before the next batch is added on top. This creates a horizontal plane of weakness called a cold joint between the two batches. Once the mix is where it should be, the curing process must be controlled to ensure that the concrete attains the desired attributes. During concrete preparation, various technical details may affect
4116-461: The concrete quality. Central mix plants must be close to the work site where the concrete will be used, since hydration begins at the plant. A concrete plant consists of large hoppers for storage of various ingredients like cement, storage for bulk ingredients like aggregate and water, mechanisms for the addition of various additives and amendments, machinery to accurately weigh, move, and mix some or all of those ingredients, and facilities to dispense
4200-483: The crack from spreading. The widespread use of concrete in many Roman structures ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon . After the Roman Empire, the use of burned lime and pozzolana
4284-562: The desert. Some of these structures survive to this day. In the Ancient Egyptian and later Roman eras, builders discovered that adding volcanic ash to lime allowed the mix to set underwater. They discovered the pozzolanic reaction . The Romans used concrete extensively from 300 BC to AD 476. During the Roman Empire, Roman concrete (or opus caementicium ) was made from quicklime , pozzolana and an aggregate of pumice . Its widespread use in many Roman structures ,
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#17328020782654368-431: The finished product. Construction aggregates consist of large chunks of material in a concrete mix, generally a coarse gravel or crushed rocks such as limestone , or granite , along with finer materials such as sand . Cement paste, most commonly made of Portland cement , is the most prevalent kind of concrete binder. For cementitious binders, water is mixed with the dry cement powder and aggregate, which produces
4452-695: The four elementary schools to be built in Bellefontaine at the turn of the century. The building was sold at public auction in 1957 to the Church of God . In 1971 McBeth School was purchased by the Logan County Historical Society for use as the Logan County Historical Museum. The historical society eventually grew out of the 3-story building and moved to its current home closer to Downtown. McBeth School has been adapted for use as an apartment building. Today
4536-554: The interlinking of the silicates and aluminate components as well as their bonding to sand and gravel particles to form a solid mass. One illustrative conversion is the hydration of tricalcium silicate: The hydration (curing) of cement is irreversible. Fine and coarse aggregates make up the bulk of a concrete mixture. Sand , natural gravel, and crushed stone are used mainly for this purpose. Recycled aggregates (from construction, demolition, and excavation waste) are increasingly used as partial replacements for natural aggregates, while
4620-404: The land in 1830. In 1898, the land was sold to Charles D. Campbell, in whose name Campbell Hill is now known. Campbell sold the hill and surrounding land to August Wagner. In 1950, the family of August Wagner deeded Campbell Hill and the surrounding 57.5 acres to the U.S. government . The government stationed the 664th Aircraft Control and Warning Squadron on the hill in 1951. This military unit
4704-540: The late 20th century, and the Big Four terminal ceased operations in 1983, Bellefontaine remains a landmark on America's railways. The city is now just a thoroughfare for CSX. In 1891, Bellefontaine became the location of the first concrete street in America. George Bartholomew invented a process for paving using Portland cement , which until then had been used in stone construction. A small section of Main Street, on
4788-406: The making of mortar. In an English translation from 1397, it reads "lyme ... is a stone brent; by medlynge thereof with sonde and water sement is made". From the 14th century, the quality of mortar was again excellent, but only from the 17th century was pozzolana commonly added. The Canal du Midi was built using concrete in 1670. Perhaps the greatest step forward in the modern use of concrete
4872-531: The material. Mineral admixtures use recycled materials as concrete ingredients. Conspicuous materials include fly ash , a by-product of coal-fired power plants ; ground granulated blast furnace slag , a by-product of steelmaking ; and silica fume , a by-product of industrial electric arc furnaces . Structures employing Portland cement concrete usually include steel reinforcement because this type of concrete can be formulated with high compressive strength , but always has lower tensile strength . Therefore, it
4956-465: The micropolis, making it the 260th most populous such area in the United States. Among all U.S. statistical areas ( CBSAs ), the Bellefontaine micropolis ranks 622nd. In Ohio , the Bellefontaine micropolis is the 37th most populous CBSA, and the 21st most populous micropolitan statistical area. By comparison, the least populous metropolitan area in the United States, Carson City, Nevada , has 52,457 residents. The least populous metropolitan area in Ohio
5040-419: The mix, are being tested and used. These developments are ever growing in relevance to minimize the impacts caused by cement use, notorious for being one of the largest producers (at about 5 to 10%) of global greenhouse gas emissions . The use of alternative materials also is capable of lowering costs, improving concrete properties, and recycling wastes, the latest being relevant for circular economy aspects of
5124-478: The mixed concrete, often to a concrete mixer truck. Modern concrete is usually prepared as a viscous fluid, so that it may be poured into forms. The forms are containers that define the desired shape. Concrete formwork can be prepared in several ways, such as slip forming and steel plate construction . Alternatively, concrete can be mixed into dryer, non-fluid forms and used in factory settings to manufacture precast concrete products. Interruption in pouring
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#17328020782655208-441: The mixing of cement and water into a paste before combining these materials with aggregates can increase the compressive strength of the resulting concrete. The paste is generally mixed in a high-speed , shear-type mixer at a w/c (water to cement ratio) of 0.30 to 0.45 by mass. The cement paste premix may include admixtures such as accelerators or retarders, superplasticizers , pigments , or silica fume . The premixed paste
5292-440: The mixture forms a fluid slurry that is easily poured and molded into shape. The cement reacts with the water through a process called concrete hydration that hardens it over several hours to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed. The hydration process
5376-465: The museum includes the Orr mansion, former home of the local Orr family; as well as an extension to the mansion that includes history exhibits from around the county. The Mansion portion of the building has been completely restored by the historical society. Day-to-day operations in the museum and The Logan County Historical Society are supported by a Logan County tax levy and donations received from visitors to
5460-496: The museum. The Bellefontaine Regional Airport is located about 5 miles from the downtown business district. The airport replaced the Bellefontaine Municipal Airport in 2002 and is one of 2 new airports opened to the public in Ohio in the past 30 years. U.S. 68 passes north-south through Bellefontaine. U.S. 33 passes through the north side of Bellefontaine. Ohio State Route 47 passes through
5544-692: The outset of the Northwest Indian War . The expedition was led by Benjamin Logan , namesake of Logan County. Blue Jacket and his followers relocated further northwest to the Maumee River . Beginning in the 1800s, American Revolutionary War veterans and others from Virginia and elsewhere began settling in the area of Blue Jacket's Town. Bellefontaine is on or near the edge of the Virginia Military District , where
5628-505: The paper had not printed in 13 years. The Bellefontaine Examiner is the only daily newspaper published for Logan County. The Examiner is the latest in a series of newspapers which have been published in Bellefontaine: This article about an Ohio newspaper is a stub . You can help Misplaced Pages by expanding it . Bellefontaine, Ohio Bellefontaine ( / b ɛ l ˈ f aʊ n t ən / bel- FOWN -tən )
5712-428: The past, lime -based cement binders, such as lime putty, were often used but sometimes with other hydraulic cements , (water resistant) such as a calcium aluminate cement or with Portland cement to form Portland cement concrete (named for its visual resemblance to Portland stone ). Many other non-cementitious types of concrete exist with other methods of binding aggregate together, including asphalt concrete with
5796-405: The population. There were 5,319 households, of which 34.1% had children under the age of 18 living with them, 45.7% were married couples living together, 14.4% had a female householder with no husband present, and 35.4% were non-families. 30.5% of all households were made up of individuals, and 11.9% had someone living alone who was 65 years of age or older. The average household size was 2.43 and
5880-506: The properties or increase the performance envelope of the mix. Design-mix concrete can have very broad specifications that cannot be met with more basic nominal mixes, but the involvement of the engineer often increases the cost of the concrete mix. Concrete mixes are primarily divided into nominal mix, standard mix and design mix. Nominal mix ratios are given in volume of Cement : Sand : Aggregate {\displaystyle {\text{Cement : Sand : Aggregate}}} . Nominal mixes are
5964-468: The quality and nature of the product. Design mix ratios are decided by an engineer after analyzing the properties of the specific ingredients being used. Instead of using a 'nominal mix' of 1 part cement, 2 parts sand, and 4 parts aggregate (the second example from above), a civil engineer will custom-design a concrete mix to exactly meet the requirements of the site and conditions, setting material ratios and often designing an admixture package to fine-tune
6048-650: The royal palace of Tiryns , Greece, which dates roughly to 1400 to 1200 BC. Lime mortars were used in Greece, such as in Crete and Cyprus, in 800 BC. The Assyrian Jerwan Aqueduct (688 BC) made use of waterproof concrete . Concrete was used for construction in many ancient structures. Mayan concrete at the ruins of Uxmal (AD 850–925) is referenced in Incidents of Travel in the Yucatán by John L. Stephens . "The roof
6132-411: The strength of the concrete bonding to resist tension. The long-term durability of Roman concrete structures has been found to be due to its use of pyroclastic (volcanic) rock and ash, whereby the crystallization of strätlingite (a specific and complex calcium aluminosilicate hydrate) and the coalescence of this and similar calcium–aluminium-silicate–hydrate cementing binders helped give the concrete
6216-497: The surface of concrete for a decorative "exposed aggregate" finish, popular among landscape designers. Admixtures are materials in the form of powder or fluids that are added to the concrete to give it certain characteristics not obtainable with plain concrete mixes. Admixtures are defined as additions "made as the concrete mix is being prepared". The most common admixtures are retarders and accelerators. In normal use, admixture dosages are less than 5% by mass of cement and are added to
6300-535: The surfaces of the aggregate together, and is typically the most expensive component. Thus, variation in sizes of the aggregate reduces the cost of concrete. The aggregate is nearly always stronger than the binder, so its use does not negatively affect the strength of the concrete. Redistribution of aggregates after compaction often creates non-homogeneity due to the influence of vibration. This can lead to strength gradients. Decorative stones such as quartzite , small river stones or crushed glass are sometimes added to
6384-655: The various ingredients used to produce a given quantity of concrete, the cement is the most energetically expensive. Even complex and efficient kilns require 3.3 to 3.6 gigajoules of energy to produce a ton of clinker and then grind it into cement . Many kilns can be fueled with difficult-to-dispose-of wastes, the most common being used tires. The extremely high temperatures and long periods of time at those temperatures allows cement kilns to efficiently and completely burn even difficult-to-use fuels. The five major compounds of calcium silicates and aluminates comprising Portland cement range from 5 to 50% in weight. Combining water with
6468-439: The water content or adding chemical admixtures increases concrete workability. Excessive water leads to increased bleeding or segregation of aggregates (when the cement and aggregates start to separate), with the resulting concrete having reduced quality. Changes in gradation can also affect workability of the concrete, although a wide range of gradation can be used for various applications. An undesirable gradation can mean using
6552-482: The west side of the Logan County Courthouse , was the first to be paved using that process. When that proved successful, Court Avenue , which runs along the south side of the courthouse, was paved with concrete. While Main Street is now paved with asphalt, Court Avenue has retained its original concrete pavement for more than 100 years. At its centennial, the street was closed to vehicular traffic and
6636-524: Was Smeaton's Tower , built by British engineer John Smeaton in Devon , England, between 1756 and 1759. This third Eddystone Lighthouse pioneered the use of hydraulic lime in concrete, using pebbles and powdered brick as aggregate. A method for producing Portland cement was developed in England and patented by Joseph Aspdin in 1824. Aspdin chose the name for its similarity to Portland stone , which
6720-416: Was $ 37,189, and the median income for a family was $ 43,778. The per capita income for the city was $ 20,917. About 19.9% of families and 23.6% of the population were below the poverty line , including 38.9% of those under the age of 18 and 10.9% of those ages 65 and older. As of the census of 2010, there were 13,370 people, 5,415 households, and 3,420 families residing in the city. The population density
6804-442: Was 1,331.7 inhabitants per square mile (514.2/km ). There were 6,115 housing units at an average density of 609.1 per square mile (235.2/km ). The racial makeup of the city was 90.1% White , 4.3% African American , 0.2% Native American , 1.2% Asian , 0.5% from other races , and 3.7% from two or more races. Hispanic or Latino of any race were 1.9% of the population. There were 5,415 households, of which 35.2% had children under
6888-602: Was greatly reduced. Low kiln temperatures in the burning of lime, lack of pozzolana, and poor mixing all contributed to a decline in the quality of concrete and mortar. From the 11th century, the increased use of stone in church and castle construction led to an increased demand for mortar. Quality began to improve in the 12th century through better grinding and sieving. Medieval lime mortars and concretes were non-hydraulic and were used for binding masonry, "hearting" (binding rubble masonry cores) and foundations. Bartholomaeus Anglicus in his De proprietatibus rerum (1240) describes
6972-622: Was quarried on the Isle of Portland in Dorset , England. His son William continued developments into the 1840s, earning him recognition for the development of "modern" Portland cement. Reinforced concrete was invented in 1849 by Joseph Monier . and the first reinforced concrete house was built by François Coignet in 1853. The first concrete reinforced bridge was designed and built by Joseph Monier in 1875. Prestressed concrete and post-tensioned concrete were pioneered by Eugène Freyssinet ,
7056-621: Was responsible for monitoring for possible aerospace attacks from the Soviet Union during the Cold War . The 664th AC&WS and similar military units were eventually superseded by the North American Aerospace Defense Command (or NORAD). The base in Bellefontaine was closed in 1969. The Ohio Hi-Point Vocational-Technical District opened a school atop the hill in 1974. The school is now known as
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