1.
Concrete
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Concrete is a composite material composed of coarse aggregate bonded together with a fluid cement that hardens over time. Most concretes used are lime-based concretes such as Portland cement concrete or concretes made with other hydraulic cements, when aggregate is mixed together with dry Portland cement and water, the mixture forms a fluid slurry that is easily poured and molded into shape. The cement reacts chemically with the water and other ingredients to form a matrix that binds the materials together into a durable stone-like material that has many uses. Often, additives are included in the mixture to improve the properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials embedded to provide tensile strength, famous concrete structures include the Hoover Dam, the Panama Canal, and the Roman Pantheon. The earliest large-scale users of technology were the ancient Romans. The Colosseum in Rome was built largely of concrete, and the dome of the Pantheon is the worlds largest unreinforced concrete dome. Today, large concrete structures are made with reinforced concrete. After the Roman Empire collapsed, use of concrete became rare until the technology was redeveloped in the mid-18th century, today, concrete is the most widely used man-made material. The word concrete comes from the Latin word concretus, the passive participle of concrescere, from con-. Perhaps the earliest known occurrence of cement was twelve years ago. A deposit of cement was formed after an occurrence of oil shale located adjacent to a bed of limestone burned due to natural causes and these ancient deposits were investigated in the 1960s and 1970s. On a human timescale, small usages of concrete go back for thousands of years and 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 houses, concrete floors. The cisterns were kept secret and were one of the reasons the Nabataea were able to thrive in the desert, some of these structures survive to this day. In the Ancient Egyptian and later Roman eras, it was re-discovered that adding volcanic ash to the mix allowed it to set underwater, similarly, the Romans knew that adding horse hair made concrete less liable to crack while it hardened, and adding blood made it more frost-resistant. Crystallization of strätlingite and the introduction of pyroclastic clays creates further fracture resistance, german archaeologist Heinrich Schliemann found concrete floors, which were made of lime and pebbles, in the royal palace of Tiryns, Greece, which dates roughly to 1400–1200 BC. Lime mortars were used in Greece, Crete, and Cyprus in 800 BC, the Assyrian Jerwan Aqueduct made use of waterproof concrete
2.
Asphalt
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Asphalt, also known as bitumen is a sticky, black and highly viscous liquid or semi-solid form of petroleum. It may be found in deposits or may be a refined product. Until the 20th century, the term asphaltum was also used, the word is derived from the Ancient Greek ἄσφαλτος ásphaltos. The primary use of asphalt/bitumen is in 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, the terms asphalt and bitumen are often used interchangeably to mean both natural and manufactured forms of the substance. In American English, asphalt is the carefully refined residue from the process of selected crude oils. Outside the United States, the product is often called bitumen, geologists often prefer the term bitumen. Common usage often refers to forms of asphalt/bitumen as tar. Naturally occurring asphalt/bitumen is sometimes specified by the crude bitumen. Its viscosity is similar to that of cold molasses while the material obtained from the distillation of crude oil boiling at 525 °C is sometimes referred to as refined bitumen. The Canadian province of Alberta has most of the reserves of natural bitumen, covering 142,000 square kilometres. Additionally, most natural bitumens contain organosulfur compounds, resulting in a sulfur content of up to 4%. Nickel and vanadium are found in the <10 ppm level, as is typical of some petroleum, the substance is soluble in carbon disulfide. It is commonly modelled as a colloid, with asphaltenes as the dispersed phase, and it is almost impossible to separate and identify all the different molecules of asphalt, because the number of molecules with different chemical structure is extremely large. Asphalt/bitumen can sometimes be confused with tar, which is a visually similar black. During the early and mid-20th century when town gas was produced, coal tar was a readily available byproduct, the addition of tar to macadam roads led to the word tarmac, which is now used in common parlance to refer to road-making materials. However, since the 1970s, when natural gas succeeded town gas, other examples of this confusion include the La Brea Tar Pits and the Canadian oil sands, both of which actually contain natural bitumen rather than tar. Pitch is another term used at times to refer to asphalt/bitumen
3.
Road surface
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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, cobblestone and granite setts were extensively used, Road surfaces are frequently marked to guide traffic. Today, permeable paving methods are beginning to be used for low-impact roadways and walkways, asphalt, sometimes called flexible pavement due to the nature in which it distributes loads, has been widely used since the 1920s. The viscous nature of the bitumen binder allows asphalt concrete to sustain significant plastic deformation, most asphalt surfaces are laid on a gravel base, which is generally 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. Depending on the temperature at which it is applied, asphalt is categorized as hot mix, warm 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, cold mix asphalt is often 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 generally be constructed for primary highways having an average annual daily traffic load greater than 1200 vehicles per day. Advantages of asphalt roadways include relatively low noise, relatively low cost compared with other paving methods, in the mid-1960s, rubberized asphalt was used for the first time, mixing crumb rubber from used tires with asphalt. Also, application of rubberized asphalt is more temperature-sensitive, and in many locations can only be applied at times of the year. Study results of the long-term acoustic benefits of rubberized asphalt are inconclusive, compared to traditional passive attenuating measures, rubberized asphalt provides shorter-lasting and lesser acoustic benefits at typically much greater expense. Concrete surfaces are created using a mix of Portland cement, coarse aggregate, sand. In many cases there will also be Portland cement substitutes added and this can reduce the cost of the concrete and improve its physical properties. The water allows the mix to combine molecularly in a reaction called hydration. Concrete surfaces have been refined into three types, jointed plain, jointed reinforced and continuously reinforced. The one item that each type is the jointing system used to control crack development. Jointed plain concrete pavements contain enough joints to control the location of all the expected shrinkage cracks, the concrete cracks at the joints and not elsewhere in the slabs. Jointed plain pavements do not contain any steel reinforcement, however, there may be smooth steel bars at transverse joints and deformed steel bars at longitudinal joints
4.
Road
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Roads consist of one or two roadways, each with one or more lanes and any associated sidewalks and road verges. Roads that are available for use by the public may be referred to as parkways, avenues, freeways, interstates, highways, or primary, secondary, and tertiary local roads. In urban areas roads may diverge through a city or village and be named as streets, serving a function as urban space easement. Modern roads are normally smoothed, paved, or otherwise prepared to allow easy travel, historically many roads were simply recognizable routes without any formal construction or maintenance. In the United Kingdom there is ambiguity between the terms highway and road. The Highway code details rules for road users and this includes footpaths, bridleways and cycle tracks, and also road and driveways on private land and many car parks. Vehicle Excise Duty, a use tax, is payable on some vehicles used on the public road. The definition of a road depends on the definition of a highway, in the United States, laws distinguish between public roads, which are open to public use, and private roads, which are privately controlled. The assertion that the first pathways were the trails made by animals has not been universally accepted, others believe that some roads originated from following animal trails. The Icknield Way is given as an example of type of road origination. By about 10,000 BC, rough roads/pathways were used by human travelers, the worlds oldest known paved road was constructed in Egypt some time between 2600 and 2200 BC. Stone-paved streets are found in the city of Ur in the Middle East dating back to 4000 BC, corduroy roads are found dating to 4000 BC in Glastonbury, England. The Sweet Track, a timber causeway in England, is one of the oldest engineered roads discovered. Built in winter 3807 BC or spring 3806 BC, tree-ring dating enabled very precise dating and it was claimed to be the oldest road in the world until the 2009 discovery of a 6, 000-year-old trackway in Plumstead, London. Brick-paved streets were used in India as early as 3000 BC, in 500 BC, Darius I the Great started an extensive road system for Persia, including the Royal Road, which was one of the finest highways of its time. The road remained in use after Roman times, a hybrid of road transport and ship transport beginning in about 1740 is the horse-drawn boat in which the horse follows a cleared path along the river bank. From about 312 BC, the Roman Empire built straight strong stone Roman roads throughout Europe and North Africa, at its peak the Roman Empire was connected by 29 major roads moving out from Rome and covering 78,000 kilometers or 52,964 Roman miles of paved roads. In the 8th century AD, many roads were built throughout the Arab Empire, the most sophisticated roads were those in Baghdad, which were paved with tar
5.
Dowel bar retrofit
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A dowel bar retrofit is a method of reinforcing cracks in highway pavement by inserting steel dowel bars in slots cut across the cracks. It is a technique several states have used to address faulting in older jointed plain concrete pavements. The typical approach is to saw cut and jackhammer out the slots for the dowels, following dowel placement the slots are then typically backfilled with a non-shrink concrete mixture and the pavement is diamond-ground to restore smoothness. As a vehicle travels on jointed concrete roads the weight of the passes from one concrete panel to the next. As the vehicle traverses the joints its weight is placed on the edge of the panel and this can cause cracks as pavement shears off the edge of the panel. On older highways built in the early-to-mid 20th century, dowel bars were placed across the joints to help transfer the load from one panel to the next and this was discontinued because the dowel bars tended to corrode and required frequent replacement. Stainless steel dowel bars are more resistant to corrosion, but stainless steel is expensive compared to other materials. Over time the joints and roadbed tended to break down under stress, resulting in cracks and displacement of the panels. Most highways in the United States built as part of the Interstate Highway System from the 1950s to the 1980s relied solely upon aggregate interlock, in contemporary highway construction since the mid-1990s, dowel bars are once again placed across joints and at intervals along the pavement. Today, dowel bars are coated with epoxy to prevent the problems seen in earlier installations. Many states are retrofitting older highways with epoxy-coated dowel bars, the retrofit begins with cutting of six slots across all transverse joints or cracks. The slots are cut with ganged diamond saws that make six cuts in each wheel path, the concrete between the saw cuts is then removed with lightweight jackhammers. The epoxy-coated dowel bars are placed in the slots, then the slots are filled with grout, the final step is to diamond-grind the joint to remove both excess grout and any displacement of the panels. The final step often involves diamond-grinding of the road surface to remove any bumps or dips. Without the dowel bar retrofit this grinding would have to be repeated every six to eight years, dowel Bar Retrofit has been proven to outlast Asphalt Overlay by at least ten years, and significantly improves ride quality. For dowel bar retrofit, dowels, bond breaker, expansion caps, dowel bar support chairs, foam core insert, caulking filler, non-shrink concrete backfill material, the dowels need to be smooth, round, epoxy and made of bond breaker coated steel conforming to requirements. The bond breaker is to be applied on all surfaces of the dowel bar, the expansion caps belong at each end of the dowel bar and the dowel bar support chairs are used to firmly hold the dowels centered in the slots during backfill operations. The foam core insert is used to re-establish the joint or crack, the caulking filler is used to prevent backfill material from flowing into the joint or crack
6.
Road slipperiness
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Road slipperiness is the technical term for the cumulative effects of snow, ice, water, loose material and the texture of the road surface on the traction produced by the wheels of a vehicle. Public works agencies spend a portion of their budget measuring and reducing road slipperiness. Even a small increase in slipperiness of a section of road can increase the accident rate of the section of road tenfold, maintenance activities affecting slipperiness include drainage repair, snow removal and street sweeping. More intensive measures may include grinding or milling a surface that has worn smooth, a specific road safety problem is split friction or μ - split, when the friction significantly differs between the left and the right wheelpath. Split friction may cause jack-knifing of articulated trucks, while trucks with towed trailers may experience trailer swing phenomena, split friction may be caused by an improper road spot repair that results in high variance of texture and colour across the road section. The two ways to measure road slipperiness are surface friction testing and stopping distance testing, friction testing can use surface friction testers or portable friction testers, and involves allowing a freely moving object, usually a wheel, to move against the surface. By measuring the resistance experienced by the wheel, the friction between the ground and the wheel can be found, stopping distance testing involves performing an emergency stop in a test vehicle and measuring the distance required to come to a stop. This has the advantage of measuring the full stopping distance, while measuring the skid marks only measures the distance from the point where the wheels began to lock or slip. Measurement of skidding resistance is not yet universally harmononised despite a number of such as FEHRLs HERMES project. The European Standards Organisation has been working on the topic for years through its committee CEN/TC227 - Road materials. This project will provide a synopsis of the current state of scientific understanding, Road slipperiness can contribute to car accidents. In 1997, over 53,000 accidents were caused by roads in the United Kingdom out of an estimated 4,000,000 accidents. As such, road agencies have a number of approaches to decreasing road slipperiness, most roads are designed with a convex camber to provide sufficient drainage, thereby allowing surface water to drain out of the road. Trouble sections include entrances and exits of banked outercurves, where the slope is close to zero. Unless these sections have a grade of at least 0. 4–0. 5%. Storm drains may be installed at intervals and modern paving materials are designed to provide high friction in most conditions. Permeable paving allows water to soak through the material, reducing slipperiness in very adverse conditions. Road slipperiness can be prevented or delayed by proper pavement design, the aggregate used in the pavement should be selected with care, as certain aggregates such as dolomite may polish, or wear smooth under the action of tires
7.
Diamond blade
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A diamond blade is a saw blade which has diamonds fixed on its edge for cutting hard or abrasive materials. Diamond blades are available in different shapes, Circular diamond saw blades are the most widely used type of diamond blade, a diamond gang saw blade is a long steel plate with diamond segments welded onto it. Normally, tens or hundreds of diamond saw blades are used together to saw raw stone blocks. A diamond band saw blade is a closed steel band with diamonds fixed on one edge of the band. Diamond blades designed for specific uses include marble, granite, concrete, asphalt, masonry, general purpose blades are also available. Vacuum brazed diamond saws are manufactured by welding synthetic diamond particles to the edge of the circular saw blade in a vacuum brazing furnace. All of the particles are on the exterior cutting edge of the blade. Finer synthetic diamond grits will reduce the chipping of tile and burring of steel, larger diamond grits will provide a higher cutting speed, but will be more likely to cause chipping, burring, or cracking. Fire departments require blades to be made with a large diamond grit. An intermediate grit size is used by the production industry, sintered metal-bonded diamond blades are the most common type of blade. These blades consist of a core and diamond segments, which are made by combining synthetic diamond crystals with metal powder. The diamond segments are also known as the teeth of the blade. The steel core can vary in design, some cores have spaces between segments to provide cooling and slurry removal, while others have a single continuous rim for smoother cutting. The type of core that can be used depends on the type of materials that the blade is designed to cut. A wholly sintered diamond blade is made by putting the core, together with the diamonds. Consequently, the diameter of wholly sintered diamond blades is not very large, because it is participating in the sintering process, the steel core cannot be quenched, so the hardness and strength of the core are not very high. This means that these types of diamond blade may deform in high-load and high-intensity cutting processes, silver brazed and laser welded diamond blades do not have this weakness because their diamond segments and steel core are treated separately. Silver brazed diamond blades diamond segments are brazed to the core using a silver solder
8.
Interstate 10 in California
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In the greater Los Angeles area, it is known as the Santa Monica Freeway and the San Bernardino Freeway, linked by a short concurrency on Interstate 5 at the East Los Angeles Interchange. Interstate 10 also has designated as either the Rosa Parks Freeway or the Redlands Freeway. The California Streets and Highways Code defines Route 10 from Route 1 in Santa Monica to Route 5 near Seventh Street in Los Angeles. Route 101 near Mission Road in Los Angeles to the Arizona state line at the Colorado River via the vicinity of Monterey Park, Pomona, Colton, Indio, and Chiriaco Summit and via Blythe. This short section of Route 10 between Route 5 and Route 101, which was defined as Route 110 until 1968, is signed overhead for I-10 eastbound. This I-5/I-10 cosigning is consistent with the Federal Highway Administrations Interstate Highway route logs that such an overlap exists for the segment of I-10 in California, I-10 is part of the California Freeway and Expressway System and is eligible for the State Scenic Highway System. However, it is not actually a scenic highway as designated by Caltrans, the Santa Monica Freeway is Route 10 from Route 1 to Route 5, as named by the State Highway Commission on April 25,1957. The section between the Harbor and San Diego freeways is also signed as the Rosa Parks Freeway, after the African American civil rights activist, the I-10 freeway is signed as the Christopher Columbus Transcontinental Highway in Santa Monica. Interstate 10 begins in the city of Santa Monica when State Route 1 turns into a freeway, SR1 exits onto Lincoln Boulevard and heads south while I-10 continues east. Soon after it enters the city of Los Angeles, I-10 has a interchange with Interstate 405. On the western edge of downtown, I-10 has an interchange with Interstate 110 to the south, I-10 then travels along the southern edge of downtown to the East Los Angeles Interchange. At the East Los Angeles Interchange, State Route 60 diverges east towards Riverside, I-10 then turns north, running concurrently with Interstate 5 for a few miles. Then, Interstate 10 heads east and merges with the traffic from the spur to US101 onto the San Bernardino Freeway, the freeway is 14 lanes wide from the Harbor Freeway interchange to the Arlington Avenue off-ramp. Most of these lanes are full at peak travel times, the remainder of the freeway varies between eight and 10 lanes in width. The whole freeway opened in 1965, with a dedication held in 1966. All three freeway-to-freeway interchanges along its length are notorious for their congestion, and are ranked among the top 10 most congested spots in the United States. Due to the traffic volume, car accidents are so common that Caltrans has constructed special Accident Investigation Sites separated from the freeway by fences. These enable the California Highway Patrol to quickly clear accidents from the traffic lanes
9.
Portland cement
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Portland cement is the most common type of cement in general use around the world, used as a basic ingredient of concrete, mortar, stucco, and most non-speciality grout. It was developed from other types of lime in England in the mid 19th century. It is a fine powder produced by heating materials in a kiln to form what is called clinker, grinding the clinker, and adding small amounts of other materials. Several types of Portland cement are available, with the most common being called ordinary Portland cement which is grey in color, Portland cement is caustic, so it can cause chemical burns. The powder can cause irritation or, with exposure, lung cancer and can contain some hazardous components such as crystalline silica. Concrete produced from Portland cement is one of the most versatile construction materials available in the world, 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. In the late 18th century, Roman cement was developed and patented in 1796 by James Parker, Roman cement quickly became popular, in 1811 James Frost produced a cement he called British cement. James Frost is reported to have erected a manufactory for making of an artificial cement in 1826, in 1843, Aspdins son William improved their cement, which was initially called Patent Portland cement, although he had no patent. In 1818, French engineer Louis Vicat invented a hydraulic lime considered the principal forerunner of Portland cement. Edgar Dobbs of Southwark patented a cement of this kind in 1811, Portland cement was used by Joseph Aspdin in his cement patent in 1824 because of the cements resemblance to Portland stone. The name Portland cement is also recorded in a directory published in 1823 being associated with a William Lockwood, a Dave Stewart, however, Aspdins cement was nothing like modern Portland cement but was a first step in the development of modern Portland cement, called a proto-Portland cement. William Aspdin had left his fathers company and in his cement manufacturing apparently accidentally produced calcium silicates in the 1840s, 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 and 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 and this became a specification for Portland cement. The Hoffman endless kiln which gave control over combustion was tested in 1860. This cement was made at the Portland Cementfabrik Stern at Stettin and it is thought that the first modern Portland cement was made there. The Association of German Cement Manufacturers issued a standard on Portland cement in 1878, by the early 20th century American-made Portland cement had displaced most of the imported Portland cement
