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79-815: The reservoir mainly serves to store waters received from the Catskill Mountains west of the Hudson River. Along with the West Branch Reservoir and Boyds Corner Reservoir , it is one of four reservoirs within the Catskill/Delaware system outside the Catskill Mountains region. The other reservoir is the Hillview Reservoir . The Kensico Reservoir also hosts fishing and boating recreation. Every year,

158-412: 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

237-433: 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

316-452: 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 ,

395-400: 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

474-434: 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

553-452: 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

632-559: 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

711-415: 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

790-461: 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

869-469: 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

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948-405: 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

1027-424: 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

1106-493: 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

1185-467: 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

1264-413: A small network of highways were privately built to carry materials from quarries at nearby Cranberry and Silver Lakes to the dam site. A camp for the workers and their families was also constructed, along with facilities such as schools for their children. To prepare for the dam construction, each individual lot of land was condemned and appraised, and the owner was paid a "fair value" for the land. Many of

1343-409: A variety of tooled processes performed. The hydration process 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

1422-660: Is a reservoir in the New York City water supply system . Formed by impounding the upper reaches of the West Branch of the Croton River , it is located in the Putnam County, New York , towns of Kent , and Carmel , about 50 miles (80 km) north of New York City . Put into service in 1895, West Branch is one of 12 reservoirs in the system's Croton Watershed , and second northernmost. Building

1501-1103: Is a Westchester County Park. The reservoir is the collecting point for the water from all six reservoirs in the Catskill Mountains: the Ashokan Reservoir , the Cannonsville Reservoir , the Neversink Reservoir , the Pepacton Reservoir , the Rondout Reservoir , and the Schoharie Reservoir . It also receives water from the Boyds Corner Reservoir and the West Branch Reservoir through the Delaware aqueduct. Water freely flows between Kensico Reservoir and Rye Lake . Through

1580-479: Is able to hold back about 30 billion US gallons (110,000,000 m) of water. It contains 1 million cubic feet (28,000 m) of masonry—as much masonry as the Egyptians used to build some of the pyramids. In one month, 2.5 million cubic yards of concrete were placed into block-shaped forms, which had to cure for three months before being swung onto the rising hyperbolic pile of dam. Frank E. Winsor

1659-473: 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

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1738-566: Is poured with reinforcing materials (such as steel rebar ) embedded to provide tensile strength , yielding reinforced concrete . In 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

1817-559: 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

1896-508: Is twice that of steel, wood, plastics, and aluminium combined. When aggregate is mixed with dry Portland cement and water , 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

1975-566: 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

2054-399: 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

2133-630: The Catskill Aqueduct before entering tunnels that carry it to the Hillview Reservoir in Yonkers , at the city's northern boundary. There it enters the city's direct water supply distribution system, flowing via tunnels through the boroughs of The Bronx , Queens , and Brooklyn . The water finally stops at Staten Island . Water in excess of New York City's needs at the West Branch Reservoir goes over its spillway and into

2212-608: The Catskill Aqueduct or the Delaware Aqueduct. After leaving Kensico, the water is treated with ultraviolet light at the New York City Department of Environmental Protection's Eastview facility, then continues on to Hillview Reservoir . At Hillview the water enters the three city tunnels which distribute water throughout the boroughs of New York City. Since the opening of the Eastview UV facility

2291-661: The Hudson River via the Delaware Aqueduct . It serves as a supplementary settling basin for these waters before releasing its flow back into the aqueduct to be carried to the Kensico Reservoir in southern Westchester County . The Delaware Aqueduct inflow to the West Branch Reservoir will be shut down from October 2024 to May 2025 while a section of the Aqueduct is being repaired. During that time,

2370-480: 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

2449-547: The 111 Westchester County residents who died in the attack. In May 2012, the roadway was reopened to pedestrian and bicycle traffic. On July 12, 2018, the New York City Department of Environmental Protection (DEP) press office announced plans for a Kensico-Eastview Connection Project. The project mainly involves constructing an approximately 2-mile long tunnel between the Kensico Reservoir and

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2528-836: The 1880s, the City faced increasing demands for water and sought to enlarge the Croton Reservoir to meet that need. The enlargement of the Croton Reservoir (with the construction of the New Croton Dam and the forming of the New Croton Reservoir ) was completed in 1906 as a part of a system of reservoirs designed to bring water from Putnam and Westchester Counties (the Croton Watershed ) to New York City. The village of Kensico, New York ,

2607-590: The Catskill Aqueduct between Kensico Reservoir and Eastview has been out of service. There is a new tunnel being built replacing the aqueduct on this section, and until its completion, all water must travel via the Delaware Aqueduct between these two points. In 2005, the DEP commenced a $ 31.4 million project to restore the Kensico Dam. The rehabilitation project consisted of reconstructing the colonnades at

2686-590: The Reservoir required displacing some of the earliest settlements along the West Branch of the Croton River including Coles Mills . It receives the flow of the upstream Boyds Corner impoundment, and, when needed, of Lake Gleneida , a controlled lake in the City supply system. Primarily, however, it receives water from the much larger Rondout Reservoir in the Catskill Mountains on the west bank of

2765-508: 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

2844-552: The West Branch Croton River, which is captured downstream by the Croton Falls Reservoir . Concrete Concrete 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,

2923-568: The West Branch Reservoir will remain open with natural flow from the Croton River and the Boyd's Corner reservoir. There will be minimal downstream releases to increase the reserve in the Croton system. West Branch Reservoir has a 20 square mile (32 km ) drainage basin, and can hold up to 8 billion US gallons (30,000,000 m ) of water at full capacity. It consists of two basins, separated by State Route 301 . During drought periods

3002-639: The West Branch also receives water pumped in from the Hudson River by the city's Chelsea Pumping Station near Beacon in Dutchess County , some 65 miles (105 km) from New York City. It was used for this purpose during the 1965–66 and 1985 droughts, as well as during May 1989. Water withdrawn from the West Branch ordinarily flows via the Delaware Aqueduct to the Kensico Reservoir in Westchester County for further settling. There it mixes with additional Catskill system water carried by

3081-643: 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

3160-526: 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

3239-399: 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

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3318-461: 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

3397-483: 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

3476-562: 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 ,

3555-729: The ends of the dam; cleaning and repairing all stone masonry surfaces on the dam; reconstructing the lower pavilions; reconstructing the dam's downstream terrace; reconstructing the spillway and spillway channel; cleaning the spillway discharge pipe; cleaning the internal galleries; installing new lighting and doors; reconstructing the Upper Gate Chamber, Lower Valve Chamber and Maintenance House; and performing grading and landscaping. Kensico Reservoir sustains an active population of gamefish, supplemented by stocking, including brown trout , lake trout , smallmouth bass , largemouth bass , perch , and grass pickerel . The size and depth of

3634-481: The ever-increasing population of New York City. A reservoir was needed that would contain waters from various new reservoirs and act as a holding tank for distribution to New York City. Kensico was surrounded by hills that came to a natural V-shape, making it an ideal area to hold a vast amount of water. To the south of Kensico was Rye Pond and Little Rye Pond in Harrison, New York , which would eventually form part of

3713-457: The families had to move to such surrounding communities as Armonk , Harrison, Valhalla, and White Plains. The village of Kensico was then flooded to make way for the reservoir. After the September 11 attacks , the road spanning the top of the Kensico Dam was closed to all traffic for fear of an attempt to destroy the dam. On September 11, 2005, a 9/11 memorial was dedicated in the dam plaza to

3792-431: 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

3871-494: The granite surrounding the main structure. The main structure of the memorial is made of steel rods that come together and point to the sky. Visitors can interact with the memorial by going inside the structure. The Rising is where the annual 9/11 commemoration takes place at Kensico Dam plaza, a ceremony honoring the Westchester residents who lost their lives that day. West Branch Reservoir The West Branch Reservoir

3950-554: 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

4029-422: The long task of digging straight down to a depth of 110 feet (34 m) to reach solid rock with no water-bearing seams. This entailed months of blasting and a number of fatal accidents. As the aqueduct neared completion in 1913, the work gangs at Kensico began laying the first of the concrete bricks of which the dam is built. The tremendous influx of workers and their families provided a period of prosperity for

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4108-406: 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

4187-531: 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

4266-419: 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

4345-478: 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

4424-441: 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

4503-411: The nearby Catskill/Delaware Ultraviolet Light Disinfection (CDUV) Facility. Before constructing the existing Kensico Dam, the old Kensico Dam had to be removed; this began in 1911. The construction of the new dam began in 1913 and was concluded in 1917—three years ahead of schedule—at a cost of more than $ 15,000,000. The dam is 1,843 feet (562 m) long, stands 307 feet (94 m) above its foundation, and

4582-541: The new reservoir. A nearby quarry in Harrison bordering Cranberry Lake provided the necessary materials for building the new dam. Although Kensico had a population of approximately 200, it was home to churches, hotels, and a railroad station . In 1905, New York State passed legislation to allow fundraising for the building of the Kensico Reservoir. The next year, final planning by the state was approved, and preliminary surveys were started. A seventeen-mile railroad spur and

4661-404: The plaza level to the top of the dam. Placards posted throughout the plaza encompass its history. In 2014, an electrical system upgrade added permanent park lighting, allowing the plaza to remain open after dark. The plaza is also home to The Rising , a memorial dedicated to victims of the 9/11 terrorist attacks who were from Westchester County. This memorial displays the names of the victims on

4740-506: 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

4819-468: 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

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4898-416: The reservoir allow lake trout in particular to thrive. Shore fishing is practiced in many areas, and boating is restricted to Department of Environmental Conservation licensed and inspected aluminum rowboats. No motorboats are permitted on the reservoir, nor are recreational watercraft such as kayaks, rafts, or canoes. In April 2020, the reservoir was stocked with 7,360 brown trout fingerlings. The reservoir

4977-474: The reservoir is stocked with over 2,000 brown trout . In April 2016, the Kensico Reservoir was stocked with 8,620 brown trout 8.5 to 9.5 inches (22 to 24 cm) long. As the population of New York City grew in the 19th century, so did the need for water. The first use of water from Westchester County came from the Old Croton Dam (forming what was called Croton Lake), which was completed in 1842. In

5056-560: The rest of the water comes from the reservoirs to which it connects. The water in the reservoir either provides New York City and Westchester County with water, or it travels down the spillway east of the main Kensico Dam, and continues down the rest of the Bronx River , eventually flowing to the East River . There are two outlets which provide water to parts of Westchester County. The water supplying New York City travels down either

5135-650: 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

5214-411: 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

5293-468: The summer and early autumn, and a Fourth of July celebration with fireworks, food trucks, and live music. Amid the COVID-19 pandemic, it also began sponsoring "Winter Wonderland," a winter-holiday-themed drive-through light experience. The plaza also provides opportunities for recreational activities, including a playground, a large lawn, gravel paths for walking and biking, and a hiking trail running from

5372-497: 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

5451-535: 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

5530-498: The surrounding area, spurring new stores, rooming houses, hotels, restaurants, and saloons. Many of the construction families remained in the area after the completion of the dam, contributing to the growth and character of Valhalla and its environs. The Kensico Reservoir was acquired as parkland in 1963 from the New York City Watershed Commission and remains the property of the DEP. Kensico Dam Plaza

5609-631: The use of pumping stations along the Delaware Aqueduct , it is possible to supply Kensico reservoir with water from the Cross River Reservoir and Croton Falls Reservoir (and indirectly, the reservoirs upstream of Croton Falls) as well as the Hudson River , however, these connections are normally not in use. The resulting body of water has a drainage basin of only 13 square miles (34 km), yet holds 30.6 billion US gallons (116,000,000 m) of water at full capacity. The reservoir's watershed provides only 2% of NYC's water supply;

5688-655: 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

5767-439: 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

5846-524: 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

5925-405: Was formerly stocked with lake trout, however, this program was discontinued after it was determined they had established a sustainable breeding population. The Kensico Dam plaza is a plaza located at the foot of the dam. Modern use of the plaza is as a public park. Historically, Westchester County's Department of Parks has hosted several community-wide events, including outdoor screenings throughout

6004-602: 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

6083-534: Was named in 1849 for a Siwanoy Indian chief, Cokenseko, who had sold most of the land surrounding White Plains to English settlers in the 1600s. In 1885, the old Kensico Dam was built south of the village of Kensico, NY as an additional source of water for New York City. The earth and gravel dam formed a small lake from water supplied by the Bronx River and the Byram River , but it was still not enough for

6162-622: 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 ,

6241-431: Was the engineer in charge of construction at Kensico, as well as the Hillview Reservoir in Yonkers and 32 miles (51 km) of the Catskill Aqueduct . New York City's main contractor built a work camp at nearby Valhalla for the 1,500 men who worked on the dam at the height of construction. The water supply board created a mounted police force to keep order. Crews were largely made up of Italian immigrants, who began

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