Cement morter

Cement mortar with various examples

1. (Dr. M K Manik ) Professor and Head of Mechanical Engineering, CCET, Bhilai [email protected] Cement mortar Basic civil engineering By

2. Cement mortar is a material used for masonry construction to fill the gap between bricks or blocks of rock Mortar binds bricks and give strength, stability and durability of building structures CEMENT MORTER

3. Motor is a mixture of binding material, sand and water, it is similar to concrete but it does not contain course aggregates Lime mortar cement mortar Surkhi mortar Mud mortar Pozzolona mortar Mortar becomes hard when sets resulting as hard aggregate structure . TYPES OF MORTERS USED

4. Mortar mixing equipments Machine mixture equipment Hand mixture equipment

5. Various proportion used for different purpose Sl. No. Works Cement : sand Proportion 1 Masonry work 1:6 to 1:8 2 Plastering work 1:3 to 1:4 3 Plastering concrete 1:3 4 pointing 1:2 to 1:3

6. CONCRETE HISTORY OF CONCRETE 2000 B.C.: Egyptians used cement in mortar when making Pyramids 27 B.C.: Roman cement made of lime and volcanic ash 1756: Smeaton rebuilt Eddystone Lighthouse 1824: Joseph Aspdin discovered and patented “Portland” cement

7. Ingredients' of CONCRETE There are three basic ingredients in the concrete mix: Portland Cement. Fine aggregates(sand and fine particles) Course aggregates (rock and stones) Water Aggregates may be course or fine Aggregate consists of large chunks of material in a concrete mix, generally a coarse gravel or crushed rocks such as limestone, or granite, along with finer materials such as sand. Cement, most commonly Portland cement, is associated with the general term concrete

8. Specification of Concrete Concrete are specified as follows : Concrete are specified by mix ratio. The strength of this concrete mix is determined by the proportion on which these cement, sand, stones or aggregates are mixed . There are various grades of concrete available in the market based on these ratios . Some of them are: M10, M20, M30, M35, etc.

9. BEST PROPRTION OF CONCRETE A concrete mixture ratio of  1 part cement ,  3 parts   sand , and  3 parts   aggregate will produce a concrete mix of approximately 3000 psi. Mixing water with the cement, sand, and stone will form a paste that will bind the materials together until the mix hardens .

10. FEW PROPORTION OF CONCRETE

11. COMMON WATER CEMENT RATIO A lower ratio leads to higher strength and durability But may make the mix difficult to work with and form Workability can be resolved with the use of plasticizers or super-plasticizers Water cement ratio of 0.45 to 0.6  is generally used in nominal mix concrete such as M10, M15 and M20 concrete construction

12. GRAPH SHOWS WATER CEMENT RATIO

13. Workability  Of concrete A  concrete  is said to be workable if it is easily Transported , Placed, Compacted And finished Without any segregation.  Workability is a property of freshly mixed concrete, and a concrete is a mixture of cement, aggregate, water & admixture .

14. Factors affecting the workability of concrete water content cement concrete Size of sand and aggregate, such as Size , Ghape , Grading, Mix design ratio And use of admixtures . Each and every process and materials involved in concrete mixing affects the workability of concrete.

15. Slump test of concrete  Concrete slump test is carried out from batch to batch to check the uniform quality of concrete during construction. The slump test is the most simple workability test of concrete, involves low cost and provides immediate results

16. Concrete Slump Test Procedure Firstly, the internal surface of the mould is cleaned carefully. Oil can be applied on the surface . The mould is then placed on a base plate. The base plate should be clean, smooth, horizontal and non-porous . The mould is filled with fresh concrete in three layers. Each layer is tamped 25 times with a steel rod. The diameter of this steel rod is  5 ⁄ 8  inch. The rod is rounded at the ends. The tamping should be done uniformly . After filling the mould, excess concrete should be removed and the surface should be leveled. When the mould is filled with fresh concrete, the base of the mould is held firmly by handles. Then the mould is lifted gently in the vertical direction and then unsupported concrete will slump. The decrease in height at the centre point is measured to nearest 5mm or 0.25 inch and it is known as ‘slump ’.

17. Cautions Required During Concrete Slump Test Inside of the mould and base should be moistened before every test. It is necessary to reduce surface friction. Prior to lifting mould, the area around the base of the cone should be cleaned from concrete which may be dropped accidentally . The mould and base-plate should be non-porous . This test should be performed in a place free of vibration or shocks. The concrete sample should be very fresh, the delay must be avoided and the test should be done just after mixing .

18. Compression test of concrete Compression testing M/C Concrete under test Concrete fails in Pressure These specimens are tested by compression testing machine After 7 days curing or 28 days curing .  Load should be applied gradually at the rate of 140 kg/cm2 per minute till the Specimens fails.   Load at the failure divided by area of specimen gives the compressive strength of concrete .

19.   curing: The concrete is flooded, ponded , or mist sprayed. This is the most effective curing method for preventing mix water evaporation. Make sure you allow proper time for water curing. Water retaining methods Use coverings such as sand, canvas, burlap, or straw that are kept continuously wet. U nless required for test at 24 hours, the cube should be placed immediately after demoulding in the curing tank or mist room The curing temperature of the water in the curing tank should be maintained at 27-30°C If curing is in a mist room, the relative humidity should be maintained at no less than 95%.

20. What is an Aggregate? We should definitely know about the aggregates because of the following Aggregates are the important constituents of the concrete which give body to the concrete and also reduce shrinkage Aggregates occupy 70 to 80 % of total volume of concrete So, can say that one should know definitely about the aggregates in depth to study more about concrete.

21. Classification of Aggregates as per Size and Shape Aggregates are classified based on so many considerations, but here we are going to discuss about their shape and size classifications in detail . Based on the shape Rounded aggregates Irregular or partly rounded aggregates Angular aggregates Flaky aggregates Elongated aggregates Flaky and elongated aggregates Based on the shape Fine aggregates Course aggregates

22. Fine Aggregate When the aggregate is sieved through 4.75mm sieve The aggregate passed through it called as fine aggregate Natural sand is generally used as fine aggregate Silt and clay are also come under this category The soft deposit consisting of sand, silt and clay is termed as loam The purpose of the fine aggregate is to fill the voids in the coarse aggregate and to act as a workability agent.

23. Different types of fine aggregates

24. Coarse Aggregate When the aggregate is sieved through 4.75mm sieve, the aggregate retained is called coarse aggregate Gravel, cobble and boulders come under this category The maximum size aggregate used may be dependent upon some conditions In general, 40mm size aggregate used for normal strengths and 20mm size is used for high strength concrete. The size range of various coarse aggregates given below.

25. Different types of course aggregates Round aggregate Flaky aggregate Irregular aggregate Angular aggregate

26. Grading curve presented by sieve analysis Coarse aggregates used in concrete making contain aggregates of various sizes. This particle size distribution of the coarse aggregates is termed as “Gradation”. The sieve analysis is conducted to determine this particle size distribution. It is this matrix that is vulnerable to all ills of concrete .

27. WHY TO DETERMINE FINENESS MODULUS? Fineness modulus is generally used to get an idea of how coarse or fine the aggregate is More fineness modulus value indicates that the aggregate is coarser And small value of fineness modulus indicates that the aggregate is finer Fineness modulus of different type of sand is as per given below Type of Sand Fineness Modulus Range Fine Sand 2.2 –  2.6 Medium Sand 2.6 – 2.9 Coarse Sand 2.9 – 3.2 Generally sand having fineness modulus more than 3.2 is not used for making good concrete. Fineness modulus can also be used to   combine two aggregate   to get the desirable grading.

28. Aggregate comprises about 85 % volume of mass concrete — —Concrete contains aggregate up to a maximum size of 150 mm —— Way particles of aggregate fit together in the mix, as influenced by the gradation, shape, and surface texture — —Grading effects workability and finishing characteristic of fresh concrete, consequently  the properties of hardened concrete — Good grading implies, sample of aggregates containing all standard fractions of aggregate in required proportion such that the sample contains minimum voids —Well graded aggregate containing minimum voids will require minimum paste to fill up the voids in the aggregate — Minimum paste means less quantity of cement and less quantity of water, hence increased economy, higher strength, lower-shrinkage and greater durability

29. HOW TO DETERMINE FINENESS MODULUS? Following procedure is adopted to calculate fineness modulus of aggregate: PROCEDURE Sieve the aggregate using the appropriate sieves (80 mm, 40 mm, 20 mm, 10 mm, 4.75 mm, 2.36 mm, 1.18 mm, 600 micron, 300 micron & 150 micron) Record the weight of aggregate retained on each sieve. Calculate the cumulative weight of aggregate retained on each sieve Calculate the cumulative percentage of aggregate retained. Add the cumulative weight of aggregate retained and divide the sum by 100. This value is termed as fineness modulus

30. Sieve Size Weight of sand Retained (g) Cumulative weight of sand retained (g) Cumulative percentage of sand retained (%) 80 mm – – – 40 mm – – –  20 mm – – – 10 mm 4.75 mm 10 10 2 2.36 mm 50 60 12 1.18 mm 50 110 22 600 micron 95 205 41 300 micron 175 380 76 150 micron 85 465 93 Pan 35 500 Total amount = 500 Total = 246 So  Fineness Modulus = 246/100 = 2.46 Calculation for So Fineness Modulus

31. Thank you To all