(3) Slump Test
Aim:-
To determine the workability or consistency of concrete mix prepared at the laboratory or the construction site during the progress of the work. It is used conveniently as a control test and gives an indication of uniformity of concrete from batch to batch.
Apparatus:-
(1) Metallic mould in the form of a frustum of a cone with internal dimensions as follow:
• Bottom diameter = 20 cm
• Top dia. = 10 cm
• Height = 30 cm
The bottom and top ends of the mould are open, parallel to each other and right angle to the axis of cone. Mould is provided with suitable guides for lifting vertically up.
(2) Metallic sheet on which mould is placed.
• Thickness of the metallic sheet should not be less than 1.6 mm.
(3) Tamping rod for
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of rod = 16 mm
• Length of rod = 0.6m (with bullet end)
Procedure:-
• The internal surface of the mould is thoroughly cleaned, free from superfluous moisture and adherence of any old set concrete before commencing the test.
• The mould is placed on a smooth, horizontal and non-absorbent surface.
• The mould is filled with concrete in 4 equal layers. Each layer is tamped with 25 strokes of tamping rod.
• After the top layer has been tamped, the concrete is struck off level with a trowel and tamping rod.
• Then the mould is removed by lifting it slowly and carefully in a vertical direction. This allows the concrete to subside. This subsidence is referred as slump of concrete.
• The difference in level between the height of the mould and that of the highest point of the subsided concrete is measured. The difference in height in mm is taken as slump of concrete.
Observations:-
Slump Patterns
• It indicates the characteristic of concrete in addition to the slump value. Following types of slumps may be possible.
(1) True
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• Three types of compression test specimens are used: cubes, cylinders and prisms. In our country, usually cube and cylinder are used. The concrete grade is based on the 150 mm size cube strength and if the cylinder is tested, the strength should be modified into equivalent cube strength.
• The size of standard cube specimen is 150 mm x 150 mm x 150 mm. If the largest nominal we of the aggregate does not exceed 20 mm, 100 mm x 100 mm x 10 mm size cubes may also be used as an alternative. Sometimes, the test is made on cylinder of size 150 mm diameter and 300 mm height.
• Details covering the preparation and testing of cubes and cylinders are covered in IS: 516 arid summarized below in the form of an experiment that may be conducted in the laboratory.
Aim:-
To prepare and test the concrete cubes and cylinders for compressive strength.
Apparatus:-
(1) 150 mm x 150 mm x 150 mm size cube moulds
(2) 150 mm diameter and 300 mm height cylindrical
Equipment = == == == == § Hydrochloric Acid § Gelatine § Tile § Test tube § Rubber Bung § Scalpel § Ruler § Stop Clock § Goggles § Measuring Cylinder Experiment =
Preliminary Work A prior experiment similar to the one outlined above, was carried out to determine the sizes of the test tubes. The surface area and volume for each tube used were § Standard Test tube Surface area = 2.69 cm2 Volume = 18 cm3 § Boiling Test tube Surface area = 5.73 cm2 Volume = 44.66 cm3 § Centrifuge Test tube Surface area = 2.26 cm2 Volume = 14.58 cm3 The surface areas to volume ratio are as follows:
For the method we are going to use to see if surface area affects the
Add 1 mL of each sample to be tested. Make sure you stir the solution before pipetting it into your tube.
of each in each test tube. (Table below showing how I am going to make
Depending on the thickness of the materials to be joined, they would next be put through one of two machines; either a three million pound press, or a series of rollers, known as levelers for the thinner material.
METHOD / MEDIA: I will use the lecture method and the mortar you see in front of you. There will be no posttest after this period of instruction. Are there any questions about your learning objectives or the method and media?
Objective: The purpose of this lab is to determine which cylinder, the 10mL or 100mL is will produce a more accurate measurement. It was also looking to determine the accuracy of measurement
In this report, we will introduce and illustrate on precast concrete, pre-stressed concrete, ready-mix concrete, reinforced concrete, terrazzo and Urbanite in details.
It is made from different materials by skill carpenters. Formwork is commonly made of Steel and Timber.
Next process is finishing in this process centrifugal force push the dense metal to the mold walls, if any impurities or bubbles flow on the inner surface of the casting walls, as a result of this next processes like machining, grinding or sand blasting are required to clean and smooth the inner diameter of of the walls.
3) Super workable concretes have the ability to fill the heavily reinforced sections without internal or external vibration, without segregation and without developing large sized voids
Some of the methods used are shovel tests, test pits, trenches, box-grid, area excavation, quadrant system and the planum method. At the beginning of an excavation, the site can be prepared by setting out a measured grid, this is to accurately keep records of objects found and test samples taken. In preparation for excavation, shovel testing and test pitting are used for soil sampling, these are done in routine breaks to test for differences in the soil. Samples are laboratory tested and screened through fine mesh to uncover artefacts and materials. The box-grid method was introduced by Sir Mortimer Wheeler, this method gives a vertical profile which shows changes in the soil and texture, and a horizontal profile will show how the site was used.
Through investigating the various properties of Cement/Concrete/Mortar, Glass, and Ceramics/Porcelain I have come to understand the chemical composition, type of bond, structure, and the daily use of each of the substances. Cement is composed of calcium which usually is acquired from limestone and silicon which is usually from sand, shale or clay (aluminosilicates). The structure of cement is in between the two extremes of an ionic and a covalent model. It is between an ionic oxide lattice and a tetrahedral covalent network. Cement when wet or when dry has both cohesive and adhesive properties. Concrete is created through the mixture of cement (filler), fine and coarse aggregate (binder), and water. With the characteristics of these materials, concrete’s type of bond attributes to its high thermal insulation properties and the strength of the material itself. Concrete is used for building materials and due to its thermal insulation properties as insulators. Mortar is a mixture of cementitious materials, water, and aggregate. For commercial use in buildings and constructions, it is useful by having water retentivity and its strength after stiffening and hardening. In addition, the content in the mortar of cement as well as air content affects the strength of the tensile bond between the mortar and the masonry. Due to the materials that compose mortar, it developed a chemical structure that is similar to its components. Also, in daily use, mortar is used for construction for buildings to attach segments together.
Of the two methods were by replacing the normal aggregates by lightweight aggregates and the other by introducing air entraining agents to increase the volume of the mix. Many light weight aggregates like pumice stone, blast furnace slag, slate and metakaolin. Use of these aggregates to some extend did not show much variation in compressive strength of concrete. The other material used as replacement to aggregates was the EPS beads. These beads reduced the weight of concrete by large amount but also affected the strength of concrete