Portland cement is the most common type of cement and typically originates from limestone. It is the key ingredient in concrete, mortar and stucco and used throughout the world. When added to concrete, it is the paste that binds the aggregate (consisting of gravel and sand) with the water.
Defined as hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product), it is “produced by pulverizing clinkers consisting of essentially hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an inter ground addition.” The concrete mix’s strength depends on the reaction of the calcium silicates with the water. The Portland Cement Association explains that, “Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients.” To produce portland cement, raw materials such as limestone, shell, or chalk are combined with clay, silica sand, shale, bauxite, fly ash, slag and iron. This mixture is heated in huge cement kilns at temperatures as high as 2,700 degrees Fahrenheit. A dark grey nodular about the size of a marble called a clinker is produced from the extreme heat and is ground into a fine powder to make the cement. Once it has cooled, a small amount of gypsum may also be added to control the setting process. Portland cement is thought to be the invention of Joseph Aspdin, a bricklayer from England, and named for its similarity to a common building stone found on the Isle of Portland in Dorset, England. Aspdin experiments were conducted in his kitchen stove where he fired ground limestone and clay together to create the first artificial cement. His new cement was a much stronger material than the standard unfired crushed limestone used during that period of time. Conco’s mission is to be the best supplier of concrete services in the Western United States and to bring expertise, experience and quality to each project. We continue to upgrade and expand facilities to better serve the growing market for public works projects, commercial, parking structures, educational, and other construction development. Sources: en.wikipedia.org/wiki/Portland_cement, cement.org/cement-concrete-basics/how-cement-is-made
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One of the mysteries that continue to baffle scientists and engineers is how the ancient Romans produced the strongest concrete in the world. Typically modern concrete buildings last about 50 to 60 years while ancient Roman concrete structures have survived through 2,000 years of environmental damage.
We know that the formula used to produce the ancient concrete is unique but no one knows for sure why it is so durable, but a group of scientists thinks they may soon find some answers. Geologists and biologists will travel to the Surtsey Island in Iceland to see if they are right. Since ancient Roman concrete was made from volcanic ash and seawater, Surtsey is a good place for answers as the entire island is made of volcanic ash and seawater caused by an underwater volcanic eruption in 1963. In 1979, researchers drilled a hole 181 meters (593 feet) deep into the volcanic rock in order to study the microbial life. The hole has been monitored since it was drilled and temperatures have cooled from 140 °C to about 130 °C. On their upcoming trip they plan to drill two more holes, one that is parallel to the original hole and another at an angle. The new holes will be deeper that the one from 1979 and is expected to penetrate 190 meters (623 feet) down to the original ocean floor before the eruption. The scientists plan to study the rock and mineral formation of the volcano and try to determine what makes the volcanic material so durable. Researchers explain that Surtsey is “unique because when it formed the mixture of heat, volcanic material, and seawater created hydrothermal minerals that strengthened the rock.” The island is much more durable than other volcanic islands as the volcanic rock is less porous and almost impervious to erosion. The hope is that by analyzing the rock from Surtsey, it may provide clues to the volcanic ash that went into ancient Roman concrete. The Conco Companies are a leading supplier of concrete services for the Western U.S. We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products. Since that time, we have taken a leading role as one of the top concrete contractors in the region. We have four regional offices serving California, Nevada, Washington, Oregon and Colorado. Source:concreteconstruction.net/business/scientists-hope-this-volcanic-island-holds-the-answer-to-stronger-concrete_c The Conco Companies have recently opened a new office in Portland, OR. While not new to the area as we have performed services for Portland from our facilities in Kent, WA, this is our first actual office in the city. The need for the office made sense as we are working on several large projects throughout the city and having a more established presence allows us to better serve our current clients as well as future clients.
One of our new projects is the Modera Glisan, a 12-story mixed-use high-rise that will offer 291 residential units on the upper floors and retail and commercial space at ground level. The project also includes an underground parking garage for approximately 223 vehicles and parking for 445 bicycles. The exterior will be comprised of granite colored brick, metal panels in two colors, glass balcony railings and aluminum storefronts. Conco will be responsible for providing concrete pumping, reinforcement, formwork, finishing, shotcrete, formwork, and construction trucking. As the job requires an aggressive schedule, we will need to use multiple placing booms. Another one of our new Portland project is 14 & Glisan, a 16-story high-rise that when finished will have 230 residential units and approximately 4,285 square feet of ground floor retail space. The tower’s exterior includes pre-cast concrete panels, brick veneer, aluminum storefront glazing and a unitized window/wall system. It will also have three levels of below grade parking to accomodate 201 vehicles. Conco’s duties include concrete pumping, reinforcement, formwork, shotcrete, and finishing as well as construction trucking services. During the course of the project, we will place 16,000 cubic yards of concrete and expect the job to take us approximately 10 months. The Conco Companies are one of the foremost suppliers of concrete services for the Western U.S. We got our start in 1959 in the Bay Area by offering clients the best value on a broad range of concrete services and products. Since that time, we have taken a leading role as top concrete contractors in the region. We have regional offices serving California, Oregon, Nevada, Colorado and Washington. As one of the nation’s leading commercial concrete contractors, The Conco Companies have undertaken many challenging jobs placing concrete over our nearly 60 years in the industry. We attributed our success to our seasoned team of professional engineers, managers, pump operators, and finishing crews as well as to our large fleet of state-of-the-art concrete pumps.
We know that many projects Conco has been a part of, and in fact a large majority of structures built since WWII, would not have been possible without the use of concrete pumps. Before pumps, cranes were used to lift large buckets known as skips to move the concrete where it was needed. Since a bucket could only hold around 2 cubic yards of concrete, it was a time-consuming, labor-intensive job. Although records indicate that the first patent for a concrete pump was applied for in 1913 by C. A. Cornell and S. A. McKee, they did not do much with it. After unsuccessfully attempting to lift concrete to the top of a German war memorial in 1927, engineer Fritz Hell began working on a pump that would handle that type of job. By 1930, the Rexnord Company in Milwaukee, WI introduced the Pumpcrete, invented by C. W. LeValley. Following WWII, Germans and other Europeans made a number of innovations to the pump’s design in order to meet the demand for more sophisticated equipment during the reconstruction period. The first hydraulic pump was developed by the Torket Company of Germany in the 1950s and operated with water. The EverythingaboutEquipment website explains that by 1957, “the Schwing Company manufactured a fully hydraulic double-cylinder pump that used an oil-operated ram with a water-flushed cylinder.” During the 1980s and 90s, many of the largest manufacturers of concrete pumps were either German or Japanese. The Conco Companies are a leading supplier of concrete services for the Western U.S. We got our start in the Bay Area in 1959 by offering clients the best value on a wide range of concrete services and products. Since that time, we have taken a leading role as one of the top concrete contractors in the region. We have four regional offices serving California, Nevada, Washington, Oregon and Colorado. Sources: ritchiewiki.com/wiki/index.php/Concrete_Pump concretepumping.com/dictionary/index.php/The_PumpCrete_by_Rexnord_or_Chain_Belt_is_believed_to_be_the_worlds_first_Concrete_Pump_1930 One of The Conco Companies most impressive projects over the last few years was providing concrete services on the Wilshire Grand Center in downtown L.A. Now after four years of construction, the 73-story tower officially opened on June 23, 2017. Costing $1.35 billion, the 1,100 ft. tall skyscraper is the tallest building west of the Mississippi. The opening ceremony for the skyscraper included local dignitaries and politicians as well as the owners of the building, Korean Air.
In addition to its towering height, the Wilshire’s slanted peaked roofline, referred to as the “sail,” stands out among the flat roof tops of the surrounding buildings. The design was instrumental in changing L.A.’s code that had required skyscrapers to have a flat roof to accommodate a helicopter in case of an emergency. In fact it is the first high-rise without a flat roof since the L.A. City Hall was built in 1928. According to the project’s lead architect, Chris Martin of AC Martin Partners, the “sail” design is based on a massive granite formation in Yosemite Valley called the Half Dome. The Wilshire is pretty spectacular at night also as the roof is lit up with rainbow-colored LED lights that can be seen for miles and will be used to project images onto the building’s face for special events. The tower also is home to the city’s highest open-air bar, and has a top floor deck that offers 360-degree views of the city. Another impressive feature is the skylight in the tower’s first-floor entrance. Comprised of “a steel cage wrapped in 475 glass panels,” Chris Martin says it was inspired by the Merced River that runs through Yosemite. It is reported that 950 people worked on the project every day. For the world’s largest continuous mat pour, Conco poured 21,200 cubic yards of concrete. By the end of the pour, we had completed a foundation that is nearly 20 ft. thick. At The Conco Companies, we are one of the leading concrete contractors in the Western U.S. and offer a wide range of quality services and products. Our experience includes providing services for commercial, educational, parking and other construction development as well as public works projects. We serve California, Washington State, Oregon, Colorado and Nevada. Source: la.curbed.com/2017/6/23/15860186/wilshire-grand-tower-los-angeles-opening |
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