Welcome to the VA Office of Small And Disadvantaged Business Utilization OSDBU. Concrete slab floors come in many forms and can be used to provide great thermal comfort and lifestyle advantages. Slabs can be onground, suspended, or a mix of both. Fox Blocks. Industrial Strength Insulated Concrete Forms ICF Call Us Toll Free at 8773692565. Inf Chapt ormation er er mation Chapt orInf CHAPTER INFORMATION TABLE OF CONTENTS 620162017 CALENDAR OF EVENTS. CCANZ STUDENT CONCRETE COMPETITION FIVE OPPORTUNITIES TO WIN A 32GB IPAD 1. How to enter Email concreteprizeccanz. Autoclaved aerated concrete AAC, also known as autoclaved cellular concrete ACC, autoclaved lightweight concrete ALC, autoclaved concrete, cellular concrete. Ready Mix Concrete Manufacturing Process Pdf' title='Ready Mix Concrete Manufacturing Process Pdf' />As a methodology for improving both factory output and quality, Lean Six Sigma LSS has gained widespread popularity. The approach, which aims to help companies. D Printing Additive Manufacturing Animation and Entertainment Architecture Services Augmented Reality AutoCAD and. The 2. 8 Day Myth National Precast Concrete Association. By Eric Barger. Throughout the construction industry, the common belief is that concrete takes 2. This evolved from a misunderstanding of what curing actually means. Some regulators characterize concrete as green if it has not cured for a certain time frame, not realizing this leads to unnecessary delays and higher project costs. An evaluation of the concepts of measured compressive strength and curing is in order to shed light on the mystery that surrounds the 2. Specifying concrete strength is normally done with a minimum compressive strength psi at a certain age days. Specified concrete compressive strength is the minimum compressive strength at which the concrete should fail in standard tests of 2. A typical concrete compressive strength specification requires 4,0. Some go a step further and mandate that concrete products cannot be installed or used until 2. This, mistakenly, has given concrete a reputation among some specifiers as being weak or inferior if it has not cured for the full 2. An arbitrary timeframe. The 2. 8 day period is an arbitrary specimen age though chosen for many good reasons for testing the compressive strength of concrete. Specification writing authorities chose 2. Such an arbitrary time frame, however, is not relevant to all mix designs. It is estimated that concrete reaches 7. A specific ratio can be determined for each specific mix design and curing process to fine tune this arbitrary age so that the mix design dictates the 2. Some mix designs reach 5,0. However, the faster concrete reaches the minimum design compressive strength, the greater the cost of the concrete. Strength measurement protocol. Measuring the compressive strength of concrete is achieved by taking a sample of concrete at the time of placement. Cylinders, measuring 1. When a failure occurs commonly referred to as a break, the compressive strength is measured by dividing the force lb measured at the time the cylinder fails by the load bearing surface area sq in. At the time of the break, the samples age is generally noted for quality assurance purposes. Asio4all 2 12 English more. Therefore, to meet the typical concrete compressive strength specification as previously noted, the break results should calculate to at least 5,0. When a specification has performance criteria of 5,0. Fortunately, more than two cylinders are typically collected for testing. Through research and empirical data collection, projection of a 2. With the accuracy of this early estimation, if a problem arises, it can be reviewed much sooner than 2. Why curing is misunderstood. Curing is the process of controlling the rate and extent of moisture loss from concrete during cement hydration 3. This would refer to a great many processes that are used to cure concrete, including steam curing, moist curing, air curing and more. It is immediately apparent that the phrase curing can have different meanings to different people. Strength and age associations behind the word curing are overwhelmingly misunderstood. Digging deeper into the curing process, hydration is the chemical process that allows concrete to go from a plastic state to a hardened state while gaining strength over time. Hydration occurs at a faster rate in the early stages after concrete placement and slows down after a month or so goes by. Many cement pastes will cease hydration before one year, and some may continue to hydrate over the course of several years 4. Because of the variable length of the hydration process, the phrase green concrete is a purely subjective characterization. With so much variation in hydration time, waiting for completion of the hydration process before testing the compressive strength of concrete would be impractical. In determining a more practical age for testing concrete strength, the 2. So, while curing does help the hydration process, 2. Simply stated, as the concrete cures and hydration takes place, the concrete gets stronger and hydration may continue long after the minimum required compressive strength is reached. Curing is a process, not a measure of strength. A specified compressive strength may be for any strength at any age of concrete. There is nothing wrong with specifying 5,0. It all depends on the mix design, circumstances and project requirements. The American Concrete Institute recognizes 2. Therefore, when a specifier calls for 5,0. In precast concrete manufacturing, however, very early attainment of specified strengths reaching the minimum required compressive strength much sooner than 2. It is extremely rare for a specifier to require a specific cure time. Rather, specifications might state that installation prior to 2. With a select mix design, concrete could easily reach its minimum required compressive strength one day after it is manufactured and therefore be specification compliant for installation. The main thing to remember is that curing is a process and not a measure of concrete strength. The 2. 8 day stipulation provides a consistent industry wide basis for comparing the compressive strength of concrete products. The 2. 8 day time frame is not directly related to whether or not a specific product meets strength requirements for a particular application. As long as the minimum compressive strength is met before the product is put in service, the time frame to reach the minimum compressive strength should not be relevant. Eric Barger is vice president of C. R. Barger Sons Inc., Lenoir City, Tenn., a family owned business spanning five generations. Eric is a civil engineer but admits that he learned all he knows by growing up in a precast plant and listening to his fathers motivational speeches. Contact him at email protected. Notes Cement Concrete FAQs, Portland Cement Association PCA www. Kosmatka, S. H., Panarese, W. C., Allen, G. E. and Cumming, S. Design and Control of Concrete Mixtures, PCA, Skokie, Ill. Curing of Concrete, April 2. Curing. 06. pdfOverview of the Concrete Hydration Process, Section 5. Monograph. 51. html. Building Code Requirements for Structural Concrete and Commentary ACI 3. ACI, Farmington Hills, Mich. ICF Swimming Pools Build. Block Insulating Concrete Forms. Insulating Concrete Forms are one of the most versatile building products on the market. They are frequently used for many structures including homes and commercial buildings, and are growing in popularity for building swimming pools. Build. Block customers have constructed retaining walls, fences and gates, fire pits and more. One increasing request for information has been ICF swimming pools. ICFs in swimming pools not only speed construction, but the insulating foam prevents more than 8. This means its much cheaper to heat your pool, but also increases the length of the pool season. ICF Builder Magazine, July 2. Build. Crete Pool Plaster, a Gigacrete product is perfectly suited as the waterproof coating and plaster directly applied to the EPS foam. Another full line of ICF pool construction products can be found at sider crete. ICF pools are being built on many types of projects. Usually found in large custom homes, they are also found in community pools and as an energy efficient addition to existing homes as well. ICFs primary component is EPS foam. They are easily formed into almost any shape imaginable and since they form an extremely flat and smooth wall, they are easily finished.