Measuring Thickness of Concrete
Measuring Thickness of Concrete Elements Using Drilled Concrete Cores
When doing construction one of the major concerns is that the work being done complies with the design specifications. In this ASTM test, C 174M-97, the thickness of a concrete pavement, slab, or structural element is determined by measuring the length of a core drilled from a concrete structure. This allows the contractor, as well as the owner, to see that the concrete is being poured to meet the requirements. (ASTM, C 174M-97, 1)
In order to complete this experiment a particular tool will be needed. It is a 3-point calipering device that will measure the length of axial elements of the core. This apparatus must conform to certain requirements. It needs to be designed so that the specimens will be held with its axis in a vertical position by three symmetrically placed studs or posts of hardened steel bearing against the lower end. The end of the studs that bear against the surface of the specimen need to be rounded to a radius of not less than 6 mm and not more than
13 mm. The apparatus needs to allow for the measuring of specimens of different nominal lengths over a range of at least 100 to 250 mm. It needs to be made in order to make a measurement at the center of the upper end of the specimen and at eight additional points spaced at equal intervals along the circumference of a circle. The device that makes contact with the end surface of the specimen needs to be rounded to a radius of 3 mm. Finally the instrument for measuring needs to be stable and sufficiently rigid to maintain its shape and alignment without a distortion or deflection of more than 0.25 mm during all normal measuring operations. Before any measurements are made, though, the apparatus needs to be calibrated with suitable gages so that errors caused by mechanical imperfections in the apparatus are known. (ASTM, C 174M-97, 1)
The measuring apparatus is not the only thing that needs to meet certain requirements. The specimen needs to be drilled with the axis normal to the surface of the structure, and the ends should be free from all conditions not typical of the surface of the structure. Any sample that shows any defects during the drilling cannot be used. If there are any particles bonded
to get an idea of how I would do my real experiment and what apparatus
HYPOTHESIS: If I use the Metric Measurement and become more familiar with it, then I will be able to convert other measurements and learn to use it and understand it better since other countries used the Metric Measurement.
Besides the known inventions and renovations of the Roman Empire, one of the building materials that the Roman Empire produced was concrete. With its strength, inexpensiveness and its easiness to work, the Roman Empire left an everlasting impact. Concrete that is a mixture of aggregate, which is usually gravel, sand or small stones, binding agents, and water is used to construct buildings and infrastructure. The first one, aggregate, gives the product its mass while the second one, binding agents, is used to harden the product. In the early times of the history, limestone powder was usually used as a binding agent in the mixture. The Romans later used “pulvis puteolanus” (pozzolanic ash), which was a fine volcanic ash as a binding agent and it allowed Romans to have strong concrete that is also durable (Yegeul, n.d.). It was easy to use
Fixed bridge (3 units)- Outline tooth crowns and place an X through tooth root to indicate which tooth is the pontic.
Scalpel 7. Ruler 8. Wooden Board 9. Measuring Cylinder-size (250cm3) 10. Top-pan Balance 11.
According to major supplies, “Use of synthetic fibers for reinforcing concrete is continuously, increasing. The increase has been considerable since 1980, but slowed somewhat in 1990, a year of substantial construction cutbacks. Apparently the construction community believes there are advantages in the use of synthetic fibers in concrete.” (Schupack) Synthetic fibers are used to improve crack control in concrete. Some reports say that synthetic fiber reinforced concrete (SFRC) would replace welded wire fabric in many slab-on-grade applications. But in reality if the welded wire fabric is placed properly it controls crack width better than the synthetic fiber reinforced concrete. In a case study of the use of synthetic fibers in reinforced concrete, the following conclusions were obtained. No matter what concrete placing job is being done, there is no substitute for good concrete practices. The use of a low fiber volume mix will help control plastic shrinkage cracks and bleeding, but not give good cracking control once the crack forms. The synthetic fibers running through a crack have a poor bond providing no shear friction. Impact and toughness tests on synthetic fiber reinforced concrete imply less edge spalling will occur. The American Concrete Institute (ACI) conducted two studies on polypropylene fiber reinforced concrete, one dealing with plastic shrinkage cracking and the other on permeability characteristics. Plastic shrinkage cracking occurs when the surface water on the concrete evaporates faster than the bleed water reaches the surface of the concrete. It was determined by the plastic shrinking cracking study that polypropylene fibers helped reduce the total plastic shrinkage crack area on test panels. Also determined is that the screeding rate affects the total crack area in polypropylene reinforced concrete, while finishing operations showed no significant effects. This study also suggests the use of longer fibers (about 0.75in.) will produce less crack area. “Permeability plays an important role in long-term durability of concrete materials. Permeability of concrete generally refers to the rate at which particular aggressive substances (water, sulfates, chloride ions, etc.) can flow through the concrete.” (Soroushian) As discussed in the plastic shrinkage study that polypropylene fibers reduce cracking. Less cracking in the concrete surface that surface would be less permeable. In the permeability study, they concentrated on the effects of chloride and the permeability of the concrete. The results of this study concluded polypropylene fibers had little effects on chloride permeability of concrete. The polypropylene fibers only help reduce plastic shrinkage cracks.
The forcible entry. Use a 10 pound sledgehammer to strike a measuring device until a buzzer sounds.
Concrete today is considered by many modern engineers and architects as a more efficient and effective alternative to steel n regards to the creation of buildings, ranging from low-story apartments to neck-breaking skyscrapers. Through the rapid growth and development of the world's major metropolises and growing cities, concrete today has become one of the most important building materials to date. According to the World Business Counsel for Sustainable Development (WBCSD), “it has become the most consumed substance on earth, only superseded by water, with three tons for each person used annually” (World). This huge demand for concrete makes the cement industry one of the world's largest carbon dioxide producers, accounting for about five percent of all man-made pollution. “Approximately one ton of carbon dioxide is put into the atmosphere for every ton of cement used” (World). The cause for this problem is the increase of the global population and the increasing demand for land and energy. It's effect is that as the population continues to increase, it forces builders and developers to meet the quota of creating unlimited amounts of infrastructure within a limited resource-filled world. Knowing this, a proposed and widely agreed solution is to make the concrete in an environmentally-conscious way that will incorporate more demolished concrete, scrap from past projects, and other recycled aggregates.
Concrete is one of the world’s most popular construction materials. Some six billion tonnes of concrete is produced each year in the world, making it approximately one ton of concrete for every human being per year (Fardis, 2012, p.116). However, the lifecycle of concrete does not make it the most sustainable building material at the moment. Because of limited natural resources, concerns over green house gases, and landfill problems, concrete production is being cut-back, or at least cannot be increased to keep up with population increase. In this essay, I will look at what makes concrete an unsustainable material and possible solutions to make concrete a more sustainable material.
Possible sources of error in this experiment include the inaccuracy of measurements, as correct measurements are vital for the experiment.
In these cases, such as building a reservoir, a huge number of concrete trucks are generally brought in in a caravan, and they pour their concrete into the forms that have been constructed onsite. In some cases, this order will put a concrete plant out of commission for a period of time due to the demand, and as such it must obviously be coordinated ahead of time.
Concrete is a composite material used widely in the construction industry. Concrete is basically a mixture of cement, water, aggregates and admixture (sometimes). Cement is a fine gray powder that consists of oxidizes calcium, silicon and aluminum. The aggregate used is normally gravel, crushed stone or sand. Admixture is a solid or liquid substance that gives a certain characteristics of the concrete. The cement reacts with water chemically and binds the aggregates together through a process called hydration during hardening or curing of concrete. It means that water helps in the hardening of the concrete while the cement bind the aggregate and also react with water to form a solid mass.
prefer to use one in which I only have to measure to half way as
From the reading, discuss the development of both concrete and the arch. Include the importance of each in the life of Rome and the results of their use.
In the past, people have always tried their own ways of using daily measurements. It was needed and used for daily trade as well as further businesses. These things could only have been made if the people knew they were being fair and honest; hence, the reason that different measurements needed to exist. Many short distance measurements were based on the lengths of the human body. The width of a thumb was used to resemble the inch, which we used today in the English System of Measurements. The foot, which is twelve inches, was compared to the length of the human foot; however, today it is derived to be longer than most people’s feet. The yard, which is equal to three feet, was inferred to be the length from the tip of the nose, to the end of the middle finger when the arm and hand are extended. The Anglo Saxons of England measured these short differences in their own ways too. The length of three barleycorns was their length of the inch (it was very close to the modern length). Then in 1066, the Normans conquered England and brought back to England the Roman tradition of the twelve inch foot. During the reign of Henry I the foot became official and was engraved on the base of a column of St. Peter’s church in London (Rowlett, R. (2001). A dictionary of units of measurement. English customary weights and measures). He also arranged the yard to be established in England as well. Although, inches, feet, yards etc. measured shorter distances, miles were used to measure much longer distances. This mile was a Roman unit, which was primarily the length of 1,000 paces of a Roman legion. The “pace” was meant to be two steps, about five feet, which measured the mile to be roughly about 5,000 feet.