Evaluating cracking in concrete procedures why cracks form in concrete structures. This is a flat, uniform foundation thats made of sturdy concrete on level ground. The total slab thickness h is usually rounded to the next higher 14 in. Based on the soil test, allowable bearing capacity of soil is 5 ksf. Slabs are one of the greatest consumers of concrete in many buildings, so reducing the slab mass can make a relatively large difference to the environmental impact of a buildings construction. Steel reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs. A reinforced concrete slab is a broad, flat plate, usually horizontal, with top and bottom surfaces parallel or nearly so.
Hollowcore units singletee units doubletee units solid concrete units beam and block floors. Grid slabs are suitable for spans of 915m and live loads of 47 knm2. Oneway and twoway slabs oneway slabs transfer the imposed. It has been the most common material used in slabs but several new. While making structural drawings of the reinforced concrete slab, the slabs are abbreviated to r. The recommendations for jointing in this publication are for pavements. Best practices of concrete pavement transition design and construction by youn su jung.
This sheet is a bond breaker, allowing the pavement and approach slab to move freely over the sleeper slab as they expand and contract. For slabs spanning in both directions published tables and charts should be used to find bending moment and shear per unit width of slab. This is a type of slabs which is generally adopted in construction of bridges. When an owner sees a crack in his slab or wall, especially if the concrete is relatively new, he automatically assumes theres something wrong.
P 100k l w frost line soil unit weight 110 pcf 40 20 slab on grade, surcharge weight 120 psf. Generally, slab on grade are classified into three types. Details of these various types of concrete, their properties and applications are discussed. A concrete slab is one of the most common foundation types found in residential home construction. After the concrete has cured and attained sufficient strength, the concrete panels are raised into place. Concrete expands and shrinks with changes in moisture and temperature. That is usually horizontal and has smaller thickness comparative of its span. After erecting the slabs and columns of a story, the columns and floor. There are three main types of slab while each main type have their subtypes.
Concrete slab types construction, cost, and applications. Another type of precast system is a slab column system that uses horizontal prestressing in two orthogonal directions to achieve continuity. Types of joints and how they work joints permit concrete to move slightly by cre a t i n g planes of weakness where cracks can form. Concrete slabs are commonly divided into the following types. Cip 14 finishing concrete flatwork what is finishing. More than 80% of housing incorporates concrete flooring of one type or another. Slabs are constructed to provide flat surfaces, usually horizontal, in building floors, roofs, bridges, and other types of structures. The concrete that is obtained by mixing the basic ingredients cement, water and aggregate will give us normal. The strength of concrete in tension is very small and so elimination of much of the tension concrete is done by the use of pan forms. Economy of construction is obviously an important consideration, but this is a qualitative argument until. Beamless slabs beamless slabs are supported only on columns and are applied mostly in large industrial and. The slab may be supported by walls, by reinforced concrete beams usually cast monolithically with the slab, by s. The choice of type of slab for a particular floor depends on many factors. This requires a small increase in the amount of steel used at the exterior support.
Therefore, rc has been widely applied in building structures. There are, however, m any variations of this procedure and a few are listed below. Manual for design and detailing of reinforced concrete to the september 20 code of practice for structural use of concrete 20 2. In general, slabs are classified as being oneway or twoway.
Construction of precast reinforced concrete structures. In this type of slab, the tension stress is eliminated in the tension side of the slab. Design methods are given for unreinforced concrete, reinforced concrete, shrinkagecompensating concrete, posttensioned concrete, fiberreinforced concrete slabs onground, and slabs onground in refrigerated. This type of slab is generally easy to construct and requires little formwork. Discussion on the reinforcement of reinforced concrete slab. The reinforced concrete floor slabs fit the clear span between columns. Rh testing gives a useful picture of the actual moisture conditions within the concrete regardless of mix, aggregate types, floor thickness, or surface conditions. While other materials are occasionally used when building home foundations, concrete slabs. A reinforced concrete footing fig 3 supports a 12x12 column reaction p100 kips at the top of footing.
Although concrete is a very strong building material, it does have its limits. This video shows the different types of slab and their subtypes. Ribbed slabs types and its advantages in construction. Slabs may be supported on two sides only or have beams on all four sides. The sleeper slab is finished smooth and allowed to cure. Slabs are used to furnish a flat and useful surface in reinforced concrete construction. They can be insulated, both underneath and on the edges. Different types of slabs in construction civil snapshot. An attempt has been need in this thesis to understand the various types of cracks occurring in. This type of slab contains square grids with deep sides. The idea is that if concrete cracks or separates at a joint it is less likely to crack. A polyethylene sheet is placed over the slab prior to placing the pavement or approach slab. It is the simplest type of slab on grade which is a composite of stiffening beams constructed from concrete around perimeter of the slab, and has a slab thickness of 100mm. Design of various types of slabs and their reinforcement.
This slab type is made up of prestressed beams and hollow blocks and are temporarily propped until set, typically after 21 days. Types of joints, how to form them and where to put them. Flat slabs are most suitable for spans of 6 9m, and for live loads of 48knm 2. Slab design reading assignment chapter 9 of text and, chapter of aci31802 introduction aci318 code provides two design procedures for slab systems. Concrete slab, a very common and important structural element, are constructed to provide flat, useful surfaces. Cip 6 joints in concrete slabs on grade what are joints. Placing excessive amounts of weight on top of a concrete slab can cause cracking. Concrete slab is a common structural element of modern building. Manual for design and detailing of reinforced concrete to. Thin concrete slabs are also used for exterior paving purpose.
Slabs are constructed to provide flat surfaces, usually horizontal in building floors, roofs, bridges, and other types of structures. The finish can be strictly functional or decorative. A concrete slab is a common structural element of modern buildings, consisting of a flat. Founded in 1904 and headquartered in farmington hills, michigan, usa, the american concrete institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensusbased standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design. In tiltup construction, either conventional or lightwei ght concrete can be used. Whether you are looking for the right domestic or commercial concrete mix for your construction job, or are just curious about the different grades of concrete and would like to know more, read on to get an understanding of these different types of concrete and their uses, or get in contact today by calling us on 01442 389105. Biaxial slabs may be marginally cheaper than solid slabs, partly due to the lower mass. The concrete protection below the reinforcement should follow the requirements of the aci code 7. Each type of cement will produce concrete with different properties. Concrete slabs are often carried directly by columns without the use of beams or. Different types of concrete grades and their uses base. The precast concrete column elements are 1 to 3 stories high. Cracks in plain and reinforced concrete posses a challenging to civil engineers from the six decades.
Types of slabs in reinforced concrete construction, slabs are used to provide flat, useful surfaces. Best practices of concrete pavement transition design and. Design and construction of joints for concrete streets. In high rises buildings and skyscrapers, thinner, precast concrete slabs are slung between the steel frames to form the floors and ceilings on each level. These type of reinforced slabs are supported directly by columns or caps, without the use of beams.
A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Concrete slabs or panels are cast on smooth surfaces on the ground or on the previously placed concrete floor. Pdf productivity analysis of concrete slab construction. Typically street pavement slabs range from 5 to 8 in.
Irregular cracks are unsightly and difficult to maintain but generally do not affect the integrity of concrete. Blended cements contain portland cement and more than 5% of either fly ash, ground slag, silica fume, or a combination of these. Slabs can be onground, suspended, or a mix of both. The slab which is casted on the surface of the earth is called a ground slab. Finishing is the operation of creating a concrete surface of a desired texture, smoothness and durability. Various types of rcc slabs civil engineering projects. Various types of precast concrete slabs free download as powerpoint presentation.
The slab may be supported by walls or by reinforced concrete beams usually cast monolithically with the slab or by structural steel beams or by columns, or by the ground. Different types of concrete are produced based on the constituent material, mix design, the method of construction, area of application, form of hydration reaction. Since this is a lengthy article, we have created a table of. Evaluating cracking in concrete bluey technologies. Twoway concrete slabs with openings the static system and the design of reinforcement. Precast concrete options are cast in a factory environment and include the following prestressed concrete options. Understanding different concrete slab problems and defects. The overall tendency is to shrink and this can cause cracking at an early age. Structural concrete structures reinforced concrete construction.
Portland cement association skokie, il abstract various types of concrete slab track are in service in japan, europe and north america. Productivity analysis of concrete slab construction by using different types of formwork article pdf available october 2016 with 1,916 reads how we measure reads. What are the 16 different types of slabs in construction. Why concrete cracks by steve vandewater cracks in concrete are extremely common but often misunderstood. Waffle slab construction process includes fixing forms, placement of pods on shuttering, installation of reinforcement between pods, installation of steel mesh on top of pods, and pouring of concrete. Are there different types of foundation engineering evaluations. The depth of a concrete slab floor is very small compared to its span. Concrete slab floors come in many forms and can be used to provide great thermal comfort and lifestyle advantages. A posttensioned slab onground foundation is simply a groundsupported concrete slab foundation that is reinforced with flexible cables that are tensioned after the. The slab may be supported by walls, by reinforced concrete beams usually cast monolithically wit. It is a horizontal structural component, with top and bottom surfaces parallel or near so. The anchorage of rc is generated by four types of rebarconcrete bonding 16. Pdf performance of concrete slabs with different reinforcing. The most common types of cement are type gp and type gb.
923 1597 1562 210 1065 1141 1659 266 211 394 724 1384 1534 312 847 987 613 421 409 1147 639 1130 428 607 1312 1160 459 69 1257 334 552 517 702 157 175 91 974