This standard has been prepared with this object in view and provides a guide to the determination of compressive strength, flexural strength and modulus of elasticity of concrete. This can be done by using a new, improved mechanical airentraining admixture or concrete containing air cells or voids throughout its volume. Procedure overview this procedure is to be used for determining the compressive strength of concrete cylinders and cores. Concrete blocks technical data short description concrete block construction has gained importance and has become a valid alternative to fired clay bricks. The fme value shall be obtained by multiplying the table values by a factor as specified in table 72 to translate lowerbound masonry compressive strength to. Specimen are prepared in concrete masonry unit making machine. For normal field applications, the concrete strength can vary from 10mpa to 60 mpa. Concrete blocks are produced in a large variety of shapes and sizes. A hollow unit is that unit which has core void area greater than 25% of the gross area. Compression strength along with resistance to water, frost and deicing chemicals are basic physicalmechanical characteristics as to this kind of product. A specified density concrete sdc called high strength.
Decorative blocks shall comply with drawings and bs en 771. The compressive strength of concrete is the most common performance measure used by the engineer in designing buildings and other structures. Decisions made in preparing such fieldremoved prisms for testing, determining the net area, and interpreting the results of compression tests require. Compressive strength of concrete blocks or concrete masonry units are required to know the suitability of these in construction works for various purposes. Non loadbearing block work includes special purpose block work such as thermally insulated external wall rendered system. The strength of concrete is majorly derived from aggregates, whereas cement and sand contribute binding and workability along with flowability to concrete this is an indepth article on compressive strength of concrete. For design of masonry, the compressive strength is current1y based on standard prism strengths, determined ei ther from testing of fully capped 2 block high. Comparative study on proportion of hollow concrete block to its compressive strength 68 different result as des fig. Use of construction masonry unit has got wide acceptance in construction industry to deal with the numerous issues associated with burnt clay bricks. Faq 0514 answering frequently asked questions the historical default minimum of 1,500 psi 10. From these 3 blocks are to be tested for block density, 8 blocks for compressive strength, 3 blocks for. Compressive strength of concrete is the strength of hardened concrete measured by the compression test. Normal weight units are made with such aggregates as sand, crushed stones and aircooled slag. The hollow load bearing concrete blocks of the standard size 400 x 200 x 200.
Part 4 with a minimum compressive strength of 5 nmm2 unless otherwise stated. Which are usually rectangular and are used in construction of masonry structure. For cube test two types of specimens either cubes of 15cm x 15cm x 15cm or 10cm x 10cm x 10cm depending upon the size of aggregate are used. Proper curing increase compressive strength of the blocks. Concrete being the major consumable material after water makes it quite inquisitive in its nature. Pdf compressive strength of sandcrete blocks orjinta. These are the concrete blocks either hollow or solid. After preparing the ends, a compressive axial load will be applied to the samples at a continuous rate until failure occurs.
Objective the tests are required to determine the strength of concrete and therefore its suitability for the job. Capability of being moulded into components of any shape and. The compressive strength of a unit is based on its gross or overall area. The test methods used should be simple, direct and convenient to apply. The compressive strength of concrete is about 4000 psi. Standard test method for compressive strength of masonry. Testing of concrete masonry blocks for compressive. This paper covers, briefly, the purpose of compressive strength of concrete test cubes, parameters, which can affect the compression strength of concrete, also some basic and advanced apparatus required for the test and the precautions for the test. Materials the quality of materials, cement concrete strength, durability and dimensional tolerance of paving blocks, etc. Aerated concrete blocks shall comply with bs en 771. We are continually striving to further enhance the. Values obtained will depend on the size and shape of the specimen, batching, mixing procedures, the methods of sampling, molding, and fabrication and the age, temperature. Concrete can be converted into precast masonry units such as hollow and solid normal and light weight concrete blocks of suitable size to be used for load and nonload bearing units for wallings.
Compression testing of concrete cylinders a nd cores rev. With increases to not only unit strength and overall assembly compressive strength, concrete masonry. Indeed, there are a wide range of options when it comes to considering which block to use. So it keeps house cool in summer and warm in winter. The hollow loadbearing concrete block of standard 400 mm x 200 mm x 200 mm size will weigh between 17 kg and 26 kg when made with normal weight aggregates. Compressive strength and absorption requirements of hollow concrete block iii. The compressive strength is measured by breaking cylindrical concrete specimens in a compression testing machine. Some of the benefits for specifying the increased strength are less grout required for partially grouted walls, less reinforcement required for walls, and reinforcement lap lengths reduced. Concrete mixtures can be designed to provide a wide range of mechanical and durability properties to meet the design requirements of a structure. It is a standard industrial practice that the concrete is classified based on grades.
Compressive strength of concrete hollow blocks formula. Pdf compressive strength of concrete masonry unit made by. This is usually called as the characteristic compressive strength of concrete fc fck. At the age of 7 days, 3 blocks per each mix ratio from the brand of cement was carried to the material laboratory of the civil engineering department. High compressive strength, resistance to weathering, impact and abrasion. Cip 35 testing compressive strength of concrete what is the compressive strength of concrete. Low maintenance, color and brilliance of masonry withstand outdoor elements. In this fourth step, the percentage of cement used in the mix was varied from 3% to 8% when casting the blocks and their compressive strength was tested after a period of 28 days. In fact, a recent article in the masonry edgethe story pole, vol. The essential ingredients of concrete are cement, aggregate sand, gravel and water. This grade is nothing but the compressive strength of the concrete cube or cylinder. The good concrete compacted by high pressure and vibration gives substantial strength to the block. Normally all units with a compressive strength exceeding 10,5 mpa are solid, i. This is the ultimate failure strength of the block, not the usually quoted compressive strength.
The capacity of concrete is reported in psi pounds per sq. This technique has numerous advantages over traditional brick wall and rcc construction. If the masonry unit strength and the mortar type are known, fme values shall be taken from tables 1 and 2 of aci 530. The appropriate cba data sheets should be consulted for more detailed information. The compressive strength of a block is not directly related to its dry density. Mcburney abstract compressivetestsof168wallsofcommonbrick,each6feetlongandabout. The class of masonry unit required is described by reference to its nominal compressive strength in mpa. Cored units shall also be measured for minimum thickness of face, shells and webs. At the age of 7 days, 3 blocks per each mix ratio from the brand of cement. Compressive strength is obviously relevant to the structural performance of the blockwork but it has no relevance to the sound insulation performance of the separating wall. Results some physical experiment also detail checked to make sure that the samples are flawless to be suitable. Compressive strength of concrete definition, importance. Insulating concrete forms wall system of building construction is an emerging technique to address the issue of shortage of building materials and faster construction.
The compressive strength that is used for design purposes and specified in catalogs or standards will only be a fraction of this. What is the compressive strength of solid concrete block. The minimum strength of blocks is 3,5 mpa and of bricks 7 mpa. For designers, compressive strength is one of the most important engineering properties of concrete. On the compressive strength prediction for concrete masonry prisms. Use of such concrete blocks are more appropriate in region where soil bricks are costly, poor in strength. Compressive strength of concrete cube test, procedure. Testing of concrete masonry blocks for compressive strength and. Concrete masonry blocks are generally made of cement, aggregate and water. Pdf comparison of compressive strength of concrete block. Load carrying capacity of hollow concrete block masonry. Pdf on jun 9, 2016, s rizaee and others published comparison of compressive strength of concrete block masonry prisms and solid. For most of the works cubical moulds of size 15cm x 15cm x 15cm are commonly used.
These included initial rate of absorption, density and water absorption test etc. Table 1 compressive strength of masonry based on the compressive strength of concrete masonry units and type of mortar used in construction ref. Structures compressive strength of concrete consequently quality of concrete manufactured is often measured by. Specimens 20 full size units shall be measured for length, width and height. Strength and elastic properties of aerated concrete block masonry prakash t m1, naresh kumar b g2 and karisiddappa3 the preliminary studies focused estimating physical and elastic properties of acb units. In line with csn 73 611 provisions, compression strength of these products is to be determined at the age of 28 days. From these 3 blocks are to be tested for block density, 8 blocks for compressive strength, 3 blocks for water absorption. Normally cement, fine sand and crush are used as the ingredients of cmu. Compressive strength of concrete is an important element in designing r. The compression strength of concrete is a measure of the concrete s ability to resist loads which tend to compress it.
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