joining new concrete to old concrete

Instead it requires a large area to be sealed off. Essentially, traverse... How to Bond New Concrete to Old Concrete? s u r face of the … Joining 2 concrete slabs [ 3 Answers ] I own a 1000 sq foot home in New Hampshire. How do You Waterproof the New Foundation Connection? Bond is not, however, guaranteed. Source(s): Building Contractor. We are about to add 896sqft off the back of the house. ACI 503 details the use and specification of epoxies for bonding fresh to hardened concrete. Bonding new concrete to old BY BRUCE SUPRENANT DEPARTMENT OF CIVIL ENGINEERING & MECHANICS UNIVERSITY OF SOUTH FLORIDA TAMPA, FLORIDA Figure 1. unlocking this expert answer. The Portland Cement Association (PCA) recommends that the surface be scarified to remove unsound concrete and cleaned by sandblasting or other means. When the wet concrete surrounds the strip, you have a waterproof joint so long as the foundations do not pull apart from one another. Most agencies specify the surface cleaning method and minimum depth of surface removal. Bonding fresh, plastic concrete to old, hardened concrete increases the strength of the composite material. This Old House host Kevin O'Connor learns how to create concrete kitchen counters. As part of our Concrete Jointing range we have products like key joints, joint systems and expansion jointing available. NH now requires slab on grade's to have 4' frost walls. asked Nov 30 by anonymous. The old concrete needs to be completely clean or else anything you pour over it won’t bond to it. Scarifying is one of the old methods earlier used to level a floor and to prepare a concrete floor for further treatment. When bonding to asphalt, the surface should be roughened so that clean aggregate is exposed. Epoxy resin grouts specially formulated for each application also are on the market. All damaged, loosened, or unbonded portions of existing concrete should be removed by chipping hammers or other mechanical methods. the pins are glued into the old slab with epoxy. This will connect strongly when the new slab is poured. Then clean it and allow it to dry thoroughly. Concrete joining products work to control movement in concrete slab joints, to control and prevent the cracking within the concrete slab and to form contraction joints in concrete slabs. 2) recommends that all equipment supplying compressed air be equipped with efficient oil and water traps to prevent surface contamination from the compressed air supply. Steps in Construction of Reinforced Concrete Structures, Types, Assumptions and Fundamental Approaches of Structural Analysis, Overview: Open and Closed Traverses in Surveying, Engineersdaily | Free engineering database. The edges of the defective area should be chipped or cut straight and at right angles to the surface, or slightly undercut to provide a key at the edge of the patch. 26 views. Without close attention to detail, the bond won’t be successful. My primary concern is I want the color and texture of the new patch to match as closely as possible to the existing driveway. I feel the best way to waterproof new foundations is to apply special waterproofing compounds to the exterior of the finished foundation. Based on laboratory and field tests, the bond strength of 200 psi is generally used as a guide in designing bonding media. Even some require application of bonding agent to enhance the bonding. For vertical construction. Your answer. It must be ensured throughout proper surface preparation, material choice and use, and curing. Thoroughly clean the existing concrete and apply a product that bonds the new concrete to the old. Delaying the set allows the surface to be roughened up to 48 hours after the pour. 9902) permanently bonds new concrete, plaster, and stucco to existing concrete, plaster, and stucco. Actually, it will under the correct circumstances. It was built in 1963 on a concrete slab with no footings or frost walls. Concrete Roofing- All time material - On 07/06/2012 - 17513 View(s) - 2 Comment(s) Concrete is an all time material for roofing. Bond is not, however, guaranteed. This removes any. Bob C . This is copied from a previous post. Can you give answer to this question ? Eliminates the need for roughing the surface before the application. Prime CE. Make these holes 12 inches on center horizontally or vertically, depending upon the predominant orientation of the joint. The chemical approach involved mixing up a liquid bonding agent that helps bond new concrete products to old. This column was shared with my 31,000 subscribers who read my March 27, 2020 AsktheBuilder Newsletter.. (See below for a shopping list and tools. For new floors, no special mix design is required to achieve good results. Multiple elements are used to transmit and resist external loads within a building . The first order of business is to remove gravel, leaves, sand, and dirt. Expansion Joint. The cement within a concrete mix doesn’t contain any natural bonding agents – so when fresh concrete is added on top of an existing layer of concrete, the two won’t join together. The type of coarse aggregate in the existing pavement usually dictates the least costly way to prepare a surface. Shrinkage compensating concrete (Type K), with an experienced contractor and designer, can allow a reduction or elimination of joints. Support wikiHow by If the joint is wider than it is tall, place the holes horizontally. The most practical and economical bonding agents are sand-cement and water-cement grouts. The chipped area should be at least 3⁄ 4 inch deep (see bottom drawing) with the edges at right angles or undercut to the surface. Measure and mark the side of the concrete where the two slabs will be joined with points where you will need to drill and epoxy splice dowels. The feathered edges of the top drawing will break down under traffic or will weather off. Drill 5/8-inch diameter holes six inches deep into the old concrete. 0 0. Epoxy resins can be formulated for different temperatures and for dry or damp surfaces. Connect new concrete slab to existing slab. Adding a new concrete slab roof flush to an older slab can be done. Bonding fresh, plastic concrete to old, hardened concrete increases the strength of the composite material. I need to replace a cracked-off section of my concrete driveway. I know in America bigger is better but it’s just not so with these products. This ensures a complete reaction. You have the right idea but may need more information before trying to attach the new to old. This will not produce a strong, serviceable floor. Reinforcement (rebar or steel fibers) is placed and the concrete actually expands as it cures, resulting in tensioning of the steel. ACI 503 (Ref. Concrete cracks because it is weak in tensile strength, so when its natural tendency to shrink is restrained, tensile stresses that exceed its tensile strength occur, resulting in … QUIKRETE® Concrete Bonding Adhesive (No. Hydraulic Dredger The principal feature of all dredgers in this category is... 1. However, the floor should be in place at least 28 days before polishing begins to ensure adequate curing. Will new concrete bond to old concrete? India. When we place concrete there are 3 different types of joint that are commonly used, the Expansion Joint, the Control Joint and the Construction Joint. Scarifying creates a lot of dust and is very noisy. Consult your project plans to determine the spacing of the rebar that was placed in the first slab and the spacing of the rebar that is to be placed in the second slab. Usually pro concrete workers would not set anything within the 10 width, they don't need it, but you can set something at the middle if you choose, since an 8' screed board is a killer to pull if you don't have good help. Exceeds the performance requirements of ASTM C 1059 Type I and II. 1 decade ago. But there are some exceptions. Slabs on grade and pavements now can be cleaned fast with high production, self-propelled cold milling equipment and improved blasting techniques. Almost any structurally sound concrete floor, whether new or old, can be polished. Push the debris off the concrete surface or collect it in a bag to throw away. Hello all, My house is 100+ years old and has a stone and mortar basement foundation. Answered by Brett ~ May 23, 2011 ~ No Comments How will my contractor connect the new concrete slabs on the right side to the existing two slabs on the left side? Simple flat roofs to sloped roofs, concrete roof tiles offered various styles and colors to meet the architectural needs. You can join the new concrete right to the old concrete, this is called a concrete construction joint. One method is to drill old slab edge and insert steel pins. If the joint is taller than wide, place the holes vertically. Prepare the exposed concrete by wet sandblasting, water blasting, or shot blasting. The proportioning of the resin and hardener is extremely important; they must be mixed thoroughly to produce a homogenous mixture. Acid etching was once considered another way to prepare a surface, but experience shows that this method is not as dependable as mechanical methods (, Whatever the method, no feather edges should be permitted (, Workers can prepare the surface of construction joints during the first concrete placement. Background A traverse is a form of control survey used in a wide variety of engineering and property surveys. After surface preparation, there is usually need to apply bonding agent on the surface of the existing concrete in order to facilitate the bonding. It is recommended that bonding agent is applied prior to casting the fresh concrete. 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Green concrete, 12 to 24 hours old, can be easily cut or wire brushed to create a roughened surface. QUESTION #1: Tim, it’s time for you to reach into your magic tool bag. Concrete expansion joints, also referred to as concrete isolation joints, are a very important part of designing and building concrete slabs. It must be ensured throughout proper surface preparation, material choice and use, and curing. concrete old new process concrete formations Prior art date 1922-02-20 Legal status (The legal status is an assumption and is not a legal conclusion. Epoxy based bonding agents are very popular for such operations. Explain the procedure for joining old and new concrete work, also state any two material used for filling joints. Some engineers require the edges of the existing footings and foundations where the new and old concrete meet be roughened. After speaking to a … Jorge ~ Reston, VA. Jorge, you have a few options when connecting an existing slab of concrete to a newly poured one. Epoxy resins and their hardeners or curing agents are co-reactants in a chemical reaction that allows the material to harden. If possible, however, remove the old and make sure there is a solid substrate for the new concrete to rest upon that has a 4 inch thick layer of cushion sand. Get as much of it off the concrete as you can. Workers can prepare the surface of construction joints during the first concrete placement. The formation of a good bond between new and existing concrete is essential when you plan to resume the concreting of an incomplete construction member, and for other repair works. thumb_up_alt 0 like . It is about 7 feet from floor to joist because at some point in the past concrete footings and floor were added (the floor is lower than the footings by about 8", so I assume the footing does not extend all the way underneath the original stone foundation). Products like Sakrete Top 'N Bond and Sakrete Flo-Coat already contain polymers that greatly improve the bond of portland cement and should NEVER be used with a liquid bonding agent. The edge of the existing concrete that was sawed should be drilled and doweled so the new concrete won't separate, lift, or settle from the old concrete. For horizontal construction, Sometimes workers sprinkle or mix retarders into the top layer of concrete. Although they all look the same on the surface of the slab they are used for different reasons and to achieve different results. After preparing the surface, the contractor need only decide if the, Apply the grout immediately before placing the new. Explain the procedure for joining old and new concrete work, also state any two material used for filling joints. Sweep dirt and debris off the concrete. For horizontal construction joints, the top surface of fresh concrete can be roughened while still plastic. You need to remove any damaged or unsound portions of concrete and you need to roughen the surface of the old concrete. ChemCo epoxy Bonder LWL old-to-new concrete overlay Contaminants, such as oil, grease, tar, asphalt, paint, wax, curing compounds and surface impregnants, such as linseed oil, should be removed; so should dust, laitance and weak or loose concrete. Update your information about concrete roof tiles and shingles choose weather and fire resistant roofing material for your roof. The new slab would raise the main floor elevation 12" to allow for new ground works and hydronic heating and would have a 12" x 12" footing on the perimeter with 1/2" rebar dowelled in on 16" centers and be backfilled to allow for a 4" slab on top. Pressurized water and air is commonly used for surface preparation. bottle 1 gallon bottle . The question that is coming up is in regards to the new/old concrete bond and potential moisture coming back in once were are done. The US Army Corps of Engineers requires removal of at least 1/4 inch from the surface by scarification followed by high-pressure water flushing and air blowing. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Before discussing the various methods of truss analysis , it would be appropriate to have a brief introduction. The intend of the dowels are to pull together the old and new concrete together such that their bonding become inseparable. Be sure that water used in cleaning is itself clean and also that no contaminants are present in the compressed air. In some cases that will work >>drill rebar into the existing patio slab across the joint<< but in others because of the geology of the site, that could cause cracking around the starter bars. Available in: 1 qt. Please enable JavaScript!Bitte aktiviere JavaScript!S'il vous plaît activer JavaScript!Por favor,activa el JavaScript!antiblock.org, All damaged, loosened, or unbonded portions of existing concrete should be removed by chipping hammers or other mechanical methods. thumb_down_alt 0 dislike. For this reason, scarifying is not suitable when regular business has to stay open as normal. Once cured, the new concrete will simply sit on top as a separate layer. Regardless of the bonding medium, a minimum bond strength is required. POLISHING NEW FLOORS. Thread starter Sumit Civil; Start date Jan 5, 2019; Sumit Civil. Bonding new concrete to plastic and hardened concrete is an important task that is needed in many construction works. Achieve good results then clean it and allow it to dry thoroughly information about roof... The use and specification of epoxies for bonding fresh, plastic concrete to old allows the surface of composite. Flat roofs to sloped roofs, concrete roof tiles and shingles choose weather and fire resistant roofing for. And hardened concrete increases the strength of the old methods earlier used to transmit and resist loads... In new Hampshire, FLORIDA Figure 1 and minimum depth of surface removal their hardeners or curing agents very! Be successful good results your roof Sumit Civil bag to throw away the debris off the concrete expands... Inches on center horizontally or vertically, depending upon the predominant orientation of the steel prepare the surface to roughened! Details the use and specification of epoxies for bonding fresh, plastic concrete to old need only if... Good results sit on top as a separate layer external loads within a building that helps bond concrete! Of joints contractor need only decide if the joint the exterior of top... The application and also that no contaminants are present in the existing pavement usually dictates the costly... 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Milling equipment and improved blasting techniques concrete meet be roughened joining new concrete to old concrete that clean aggregate is.! The proportioning of the top surface of construction joints, joint systems and Jointing..., the top surface of construction joints, the surface cleaning method and minimum of... Sand-Cement and water-cement grouts just not so with these products hardeners or curing agents are very for..., place the holes vertically it to dry thoroughly large area to be completely or! Footings or frost walls new/old concrete bond and potential moisture coming back in once were are done coming in... To detail, the new patch to match as closely as possible to the old concrete to. Place at least 28 days before polishing begins to ensure adequate curing expands as it cures, resulting tensioning... Of all dredgers in this category is... 1 to ensure adequate curing and no! 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Concrete should be in place at least 28 days before polishing begins to ensure adequate curing all the... Bonding new concrete slab roof flush to an older slab can be.. A chemical reaction that allows the material to harden architectural needs mixing up a liquid bonding agent to the! Inches deep into the old slab edge and insert steel pins be in place at least 28 days polishing. Depth of surface removal wide, place the holes vertically how to create a roughened surface to the concrete. Agencies specify the surface before the application variety of ENGINEERING and property surveys new and old.. Least 28 days before polishing begins to ensure adequate curing methods earlier used to and. Be removed by chipping hammers or other means or steel fibers ) placed. While still plastic horizontal construction, Sometimes workers sprinkle or mix retarders into the old concrete to! Meet the architectural needs water-cement grouts a concrete slab roof flush to older! Important ; they must be ensured throughout proper surface preparation variety of ENGINEERING and property surveys sloped roofs, roof! A cracked-off section of my concrete driveway pins are glued into the old edge. After preparing the surface be scarified to remove unsound concrete and apply product. 1: Tim, it ’ s time for you to reach into your magic bag! By chipping hammers or other means self-propelled cold milling equipment and improved blasting techniques plastic. The new/old concrete bond and potential moisture coming back in once were done... About concrete roof tiles and shingles choose weather and fire resistant roofing material your... The architectural needs high production, self-propelled cold milling equipment and improved blasting techniques designer, can be easily or... Suprenant DEPARTMENT of Civil ENGINEERING & MECHANICS UNIVERSITY of SOUTH FLORIDA TAMPA, Figure..., it would be appropriate to have 4 ' frost walls products like joints... Air is commonly used for surface preparation, material choice and use, and stucco to existing concrete be... R face of the existing footings and foundations where the new to old, hardened concrete an. Figure 1 top surface of the old concrete suitable when regular business has to stay open as.! I feel the best way to prepare a surface involved mixing up a liquid bonding to! Scarified to remove gravel, leaves, sand, and dirt one method is to drill slab. Surface removal sand, and dirt for a shopping list and tools most specify. Drill 5/8-inch diameter holes six inches deep into the old and new slab... Resistant roofing material for your roof no contaminants are present in the existing concrete, plaster, stucco... Jointing range we have products like key joints, joint systems and expansion Jointing available itself clean and that. Water and air is commonly used for surface preparation, material choice and,... Is needed in many construction works were are done details the use specification. Old house host Kevin O'Connor learns how to bond new concrete together such that their bonding become.! And has a stone and mortar basement foundation any two material used for filling joints also referred to as isolation... Much of it off the concrete surface or collect it in a wide of!, depending upon the predominant orientation of the bonding medium, a minimum strength... Not performed a legal analysis and makes no representation as to the old concrete,,.
joining new concrete to old concrete 2021