EXPERIMENT NO.1. : Vicat s apparatus, plunger

Transcription

1 EXPERIMENT NO.1 Name of experiment:to determine the percentage of water for normal consistency for a given sample of cement Apparatus : Vicat s apparatus with plunger of 10mm dia, measuring cylinder, weighing balance, weight box,, trowel. Theory : Standard consistency of cement is defined as that consistency witch will permit plunger to penetrate at 33.34from the top of the mould. The consistency cement paste is expressed as a percentage by wt of dry cement. Usually this percentage varies from 26% to 33%. Vicat s Apparatus : As vicat s apparatus consist of a frame bearing a movable rod of weight 300grms. At the upper end of this rod a cap is provided low rend 1.13mm n of weight 300grms. It the upper end of this rod a cap is privy deed while at the 1.13mm needle or plunger of 10mm diameter is shown in. Diagram : Vicat s apparatus, plunger Observation Table: 1.Take 400gm of cement and weight carefully and Add 20% water in Care should be taken that mining time is not less than 3min and gauging shall be counted from the time of adding water 2.Fill the paste in the mould.the excess paste to trim off and vibration are given to remove air bubbles. 3.Fix the 10mm dia. plunger in the moving rod and bring down in touch with the paste 4.Release the plunger. 5.Repeal the procedure till it penetrate 33-34mm from the top & note down the water percentage So. No Wt of cement (Gm) Percentage by wt of dry cement Amount of water added (ml) Penetration Precaution : 1) The procedure should be conducted within 3-5min 2) The reading should be taken carefully Result The percentage of water for normal consistency for the given sample of cement is.. 1

2 Experiment NO.2 Name of experiment : To determine the initial and final setting time of a given sample of cement. Apparatus : 1. vicar s apparatus mould and non-porous plate, needle 2. weighing balance, weight box 3. measuring cylinder 4. stop watch Diagram : Theory : When water is mixed to cement, a reaction start, this reaction is known as hydration. Due to this reaction the mixture of cement and water starts changing from one fluid state to a solid state This is called setting of cement In the first few minute the setting action is more predominant and after some time hardening action becomes rapid. It is defined period elapsing between the time water added to the cement and the time when the 1mm sq section needle fails to penetrate cement this block to depth of about 5mm form the bottom of the mould Generally the initial setting time of cement is not less than 30min 1. Take about 500gms of cement. 2. Add water of standard consistency. To make cement paste. 3. To make the surface of the cement paste is till smooth and level. 4. The whole assembly kept in vicat s apparatus. 5. Bring the needle in the rod gently near the surface of the test block and release it quickly allowing it to penetrate into the block and note the time 6. Repeat the procedure till the needle fails to penetrate into the test block by 5mm to 7mm from the bottom of the mould. Observation : 1. Quantity of cement = 2. Water for standard Consistency = 3. Quantity of water to be added = Observation Table : Sr.No SETTING TIME (min) DEPTH OF PENTRATION

3 Precaution : 1. Reading should be taken carefully. 2. Water cement ratio should be accurate. Result : i) The initial setting time of the cement sample is found to be.. ii) The final setting time of the cement sample is found to be.. Conclusion : 3

4 Experiment NO.06 Name of experiment : To determine impact value of aggregate Apparatus : Impact testing machine, weighing balance, weight box, tamping rod, 2.36mm IS sieve etc. Formula : Impact value= Weight of material passed through2.36mm I.S sieve Weight of aggregate Diagram : Theory : Aggregate impact Value: - With respect to concrete, aggregate toughness is usually considered the resistance of the materials to failure by impact. The most successful is the one in which a sample of standard aggregate kept in mould is subjected to 15 blows of a metal rammer of weight 14 Kgs.falling from a height of 38cms. The quantity of materials passing through 2.36mm IS sieve will indicate the toughness of the sample of aggregate. The ratio of the weight of the weight of total sample taken in expressed as a percentage this is known as aggregate impact value. IS specified that aggregate impact value shall not exceed 45% by weight for aggregate used for concrete other than wearing surface and 30% by wearing for concrete for wearing surface, such as runways, roads and pavement Aggregates are classified for type and user in the following according to their impact value. Impact Value. 1. Below Exceptionally strong aggregate Strong satisfactory for road surfacing 3. Greater than Work for road surfacing 5. Max limit in For bituminous & cement concrete For bituminous 1) Take the test sample consisting of standard aggregate passing through 12.5mm and retained on 10mm I.S. sieves. The aggregate about one third full of t mould and tamped by 25 strokes by tamping rod. Add further similar quantity of aggregate and tamp it and fill the measure. 2) Determine the net wt of aggregate in mould 3) Place the whole sample into a steel cylindrical cup fixed on the base of the machine. 4) Raise the hammer wt about 14kgs to the height of 38cm above the surfaces of aggregate 5) The sample was subjected to a total 15 such blows each derive red at an interval of not less than one sec. 6) Remove the crushed aggregate from the cup and sieve through 2.36mm 1S sieve and weight the material passed through 2.36mm 4

5 Observation: Precaution: 1 Weight of mould = W 1 2 Weight of mould+ Aggregate = 3 Weight of aggregate= W 1 4 Weight of aggregate passing through 2.36mmIS sieve=w 2 5 Weight of sample retained =W 3 1. There should not be any loss of aggregate from the mould. 2. The interval of blows should not exceed one second Result: The impact value of aggregate is found to be % Conclusion: The aggregate is aggregate. 5

6 Experiment NO. 07 Name of experiment : To determine the workability of concrete mix by slump test Apparatus : Mould, pan, trowel weighing balance weight steel rod. Diagram : Theory :The ease with which the concrete is mixed, transported and placed is called workability of concrete. Slump Test The mould used for this test in the form of a frustum of cone with internal dimension as follows i) Bottom diameter -20cm ii) Top diameter -10cm iii) Height-30cm 1. Prepare concrete mix with known proportions 2. Place the mould on a smooth flat and non absorbent surface. 3. Fill the mould with concrete to about 1/4 th the height 4. Compact the concrete with the help of steal rod 0.6m long and 16mm in diameter. 5. Fill the mould to about ½ of its height and compact it again 6. Repeat the procedure till the mould is filled completely and excess concrete is trimmed off 7. Remove the slump cone carefully in the vertical direction and on the removal of the mould the concrete subsides 8 Measure the height of concrete after subsidence Observation : 1. Proportion of concrete mix 2. Water cement ratio= 3. Weight of cement = 4. Weight of sand= 5. Weight of aggregate = 6. Ht of concrete before slump subsidence = 7. Final height of concrete after subsiding = 8. Slump height = Result : The slump value of given concrete mix is found to be.. Conclusion : 6

7 Experiment NO. 03 Name of experiment : To determine the bulking of fine aggregate i.e. [sand] Apparatus : 1. Measuring jar 2. Taping rod Theory : The volume of fine aggregate depends largely upon its moisture content. When the fine aggregate is moist each particle gets coated with a film of water due to surface tension. The particles are kept separated and hence the volume apparently increases. The increase in volume is known as Bulking The amount of Bulking increases initially with increase in water content but decrease to zero with further increase in water content over to bulking, Fine aggregate shows completely unrealistic volume. Therefore it is absolutely necessary that consideration must be given to the effect of bulking. Bulking = h 1 -h 2 h 2 X Take a container and fill the sand in loose state till it fill 2/3 rd. and its height was noted (h 1 ) 2. Fill the container with water till bulking stops. 3. Measure of sand depth when it completely saturate (h2) Observation : SAMPLE INITIAL FINAL Y (ML) PERCENTAGE Result: The bulking of sand is found to be % 7

8 Experiment NO. 04 NAME OF EXPERIMENT: To determine fineness modulus of aggregate. APPARATUS : 1) Set of : 80mm, 63mm, 40mm, 20mm, 12.5mm, 10mm, 6.3mm, 4.75mm 2) Weighing balance with weight box. 3) Tray THEORY : Fineness modulus of aggregate is an index number which gives an idea about the coarseness or fineness of an aggregate It can be written as FM. Fineness modulus. of an aggregate is approximate proportional of the average size of particles in the aggregate. In another words coarse particles of the aggregate having of Fineness modulus is determined by adding the cumulative percentage of material retained on each sieve and dividing the sum of cumulative percentage of material retained on each sieve by100 In this method, the fineness modulus of coarse fine and communed aggregate are determined separately. The value of F.M. is higher for coarse aggregate (I e stone metals etc.)are as follows For 20mm size = 6 to mm size= 6.9to7.5 For all in aggregate 20mm size = 4.8 to mm size = 5.1 to 5.5 PROCEDURE: i) Take a suitable sample of aggregate ii) Put the aggregate on the upper most sieves. iii) Sieve it as per sieve analysis. iv) Find out wt retained on each sieve. v) From that value cumulative percentage of weight retained on each was calculated. OBSERVATION TABLE : Weight of coarse aggregate = kg S.NO IS Sieve mm Weight Retained In Each Sieve (Gms) Cumulative wt Retained %Cumulative Wt Retained %Finer 8

9 PAN PRECAUTION : i) The sieve should be in the proper sequence ii) There should be no wastage of aggregate during sieving iii) The weight of the aggregate retained on each sieve should measure carefully. RESULT : Fineness modulus of aggregate is found to be. 9

10 Experiment NO. 05 Name of experiment : To determine abrasion value of given sample of aggregate Apparatus : Los angles machine, Balance to weight to accuracy of 0.1gm, 1.7mmIS sieve Theory : In abrasion test,the aggregate are tested with respect to its resistance to wear. According to these values, the suitability of the aggregate for the use of road construction. Pavement construction, water house floor is considered. The principal of Los angles abrasion test to find percentage wear due to relative rubbing action between the aggregate and steal ball, as abrasive charges. During the test pounding action of these balls also exist. Los angles machine consist of hollows cylinders closed at both ends having an inside diameter of 70mm and inside length of 50mm mounted on steel shaft about which it rotate an a horizontal axis. An opening it provided in the sample for the introduction of the test sample. Abrasion charge consist of cast iron spheres 4.8cm in dia and 390 to 445gm in weight. 1. Take 2kg of aggregate 2. choose suitable abrasion charges 3. The aggregate with abrasion change i.e.12 cast iron balls were taken and placed in the cylinder of machine 4. Rotate the machine at a speed at 30 to33 revolution per minute so as to complete revolution 5. Then the machine stop and discharge material from the machine,taking care to take out entire stone dust and sieve it through 1.7mm sieve 6. Weight the material retained on 1.7mm I.S sieve and calculate the abrasion value Observation and calculation : 1. Total wt of aggregate (w1) = 2. Wt aggregate retained on 1.75mm IS sieve.(w2)= Precaution : 1. The cylinder should properly tight for not loosing aggregate 2. The machine should be rotated in given time 3. Weight should be taken carefully Result : The abrasion value of the given aggregate Sample is % 10

11 Experiment NO-08 Name of experiment: To determine the workability of freshly mixed concrete by compaction factor test. Apparatus : Compaction factor testing machine hand weight and machine weight. Theory : Workability : To test the workably of freshly concrete, compaction factor test is carried out. This test works on the principal of determining the degree of compaction achieved by standard amount of work done by allowing the concrete to fall through a standard height the degree of compaction factor is the ratio of weight partially compacted concrete to the wt of fully compacted concrete Compaction factor = Wt of partially compacted concrete Wt of fully compacted concrete 1. Prepare the dry concrete mix in the ratio 1:2:4 ( kg cement ) 2. Add water assuming the water ratio to be 0.65 (for 2kg of cement add 910 ml at water) 3. Place the concrete mix in the upper hopper of the compaction factor apparatus and up the top level acierates 4. Open the trap in cylinder 5. Again open the trap in cylinder 6. Take the wt of cylinder concrete Compaction 7. Remove the concrete and refill the cylinder in three layers and give 25blows on each layer by tamping rod. 8. Again take the weight of cylinder with concrete and record it as weight of fully compacted concrete and calculate the compaction factor value by using formula Observation : 1. Wt of cement= 2. Wt of sand= 3. Wt of aggregate. = 4. Water cement ratio = 5. Wt of cylinder= 6. Wt of partial compacted concrete with cylinder= 7. Wt of fully Compacted concrete with cylinder= 8. Wt of partially compacted concrete with cylinder= Result The compaction for given concrete mix is found to be Conclusion The degree of workability is.and use for. 11

12 Experiment NO. 09 NAME OF EXPERIMENT : To determine compressive strength of concrete Apparatus : Cube mould of 15cm side, vibrating machine, water measuring jar,compression testing machine etc Materials : Standard sand,cement, coarse aggregate etc. Theory : The test is carried out ao study the quality of cement from compression strength point of view The test consist of determining compression strength of 7and 28 days. Compression strength of cement is the property that most decides the qualities of strength of concrete 1. Take about 1kg of cement and mix with 2kg of sand with 4kg of as coarse sand aggregate 2. The cement and sand was mixed to uni form color by towel 3. Water is mix up (px/4+3.5) % by weight of dry material (i.e. sand +sand) and mix it to obtain uniform grey color 4. The mould surface should coated from inside and joint is sealed with grease so that no water shall escape during compaction 5. Keep the mould at room temp about 24 hrs 6. Keep the mould in water for 3day, 7day and 28 day 7. Test the cube specimen on compressing testing machine for different curing. OBSERVATION TABLE: S. No. Grade 3days strength 7days strength 28days strength Average Precautions : Result : (1) The cube mould were made water tight by coating the edge by grease The compressive strength of concrete is found to be.. 12

13 Experiment NO. 10 Name of experiment : To study concrete mix design by ACI method Theory : This method of proportioning was recommended by ACI method committee 211, having gone into the details about the various method of mix designing practices The following facts have been assumed by ACI confide. i) The method makes the use of fact that over considerable range of practical proportional fresh concrete on the given slump and containing reasonable well graded aggregate will have constant total water content regardless of the variation in w/c ratio and cement content which are interrelated ii) It makes use of the dry volume of coarse aggregate per unit volume of concrete, which depends up on max sizes, and the fineness modules of fine aggregate iii)it also assumed that definite % of are presence, which is inertly proportional to maximum size o f aggregate. 1) Data to be collected a) Fineness modulus of aggregate b) Unit Wt of dry rodded coarse aggregate c) Sp. gravity of coarsers and fine aggregates d) Absorptive chacteristies of both course and fine aggregate e) Sp. Gravity of cement 2) From minimum strength specified estimate average design strength by using standard deviation or coefficient of variation 3) Find the w/c ratio from strength point of view and also from durability point of view 4) Max size of aggregate to be used is decided 5) Decide the workability in terms of slump for the type of is decided from table 6) Total wt of water in kg/m3 of concrete with selected slump, selected max size of aggregate from table. This table also gave approximate amount of accident-entrapped air in non-entrant concrete. 7) Cement content its calculated by using deviding total water content by w/c ratio. 8) The bulk volume of dry rodded aggregate per unit volume of concrete from table 9) The Wt of course aggregate is calculated by multiplying bulk volume by bulk density 10) The Solid volume of course aggregate in m 3 of concrete is calculated by using sp. gravity 11) Similarly solid volume of cement water and air is to be calculated be /m3 12) Volume of fine aggregate is obtained by subtracting from total volume of Conroe to volume of all material 13

14 Question : It is required to design a concrete mix for an air field pavement the pavement is to be designed for a minimum compression strength up to 250kg /cm2 at 28 days The lake test on the controlling link shows standard deviation of 40kg/cm2 The specific gratuity of the coarse aggregate is2.65 and in dry ridded deity is 1600kg/m3 It max size is 40mm. The specific gravity the fine aggregate. Is 2.60 and its fineness modules is 2.80 a stump cement is to be used Calculation : 1) Data collected a) Fm of fine aggregate = b) Unit wt of dry rodded course aggregate = c) Sp gratuity of course aggregate = d) Fine aggregate = e) Sp gratuity of Cement = 2) Avgas design strength a) Sag = skink b) K for 1% fall = 3) To final w/c ratio = a) Strength= b) Durability= W/c ratio= c) Size of aggregate = d) Slump e) Workability = f) Net of water = g) Net for trapped= Comment content = 4) Bulk volume of dry rodded aggregate /unit volume of Concrete = OBSERVATION TABLE : Sr.No Ingredient Wt(kg) Solid Volume(mm3) 1 Cement 2 water 3 Course aggregate 4 Footrope air 14

15 1. Density of Solid Volume = Total Volume - Volume of Fine aggregate of concrete constituent 2. Fine aggregate = Coarse aggregate = Final proportions = Thus A C I method is studied. 15