how to find Grading of coarse aggregate


      Grading of coarse aggregate


  Apparatus and materials


1.      I.S. sieve of size 40mm, 20mm, 12.5mm, 10mm, 4.75mm, 2.36mm.

2.      Coarse aggregate

3.      Vibrator


  Procedure

1.      5 kg of coarse aggregates, arranged the set of IS sieves in order with the sieve size increasing to the top, and with pan at the bottom.

2.      Before the sieves analysis was performed the Aggregate sample has to be air dried in order to avoid lumps of fine particles and to prevent clogging of finer sieves.

3.      Sieving could be done either manually or mechanically.

4.      In the manual operation the sieve was shaken giving movements in all possible directions to give chance to all particles for passing.

5.      Fineness modulus of coarse aggregate determined.

6.      Fineness modulus is defined as the sum of the cumulative % retained on the sieves of standard series divided by 100.

7.      The fineness modulus is an empirical factor and can be looked upon as the massed average size of a sieve on which the material is retained, the sieves being counted from the finest.

Comments

Post a Comment

Popular posts from this blog

how to find specific gravity of fine aggregate

Image
how to find specific gravity of fine aggregate Apparatus and material 1.       Pycnometer bottle 2.       Balance of accuracy 0.001g 3.       Vacuum source 4.       Fine aggregate    Procedure 1.         For fine aggregate particle size less than 4.75 mm 500 gram of sample taken. 2.       The pycnometer bottle should be well washed, cleaned, dried, and weighted accurately on sensitive balance. 3.       It should than be filled with water to the top of the hole, so that surface of Water in the hole is flat. 4.       The pycnometer than be dried on the outside & weighted accurately. 5.         About 500 grams of the above sample was transferred to the pycnometer & weighted. 6.       The pycnometer was filled with water and dry air entrapped in the aggregate was topped with water to the level or the hole in the cone as before and the entire front removed from the surface. 7.         The pycnometer was
Read more

Super plasticizer (SP) & VMA (viscosity modifying agent)

Image
Super plasticizer (SP) High-range water reducer, also known as super plasticizer, has made a breakthrough in concrete industry. It is an essential material component that must be used to produce SCC. The HRWRs improve the flowing ability of SCC by their liquefying and dispersing actions. They reduce the yield stress and plastic viscosity of concrete by their liquefying action and thus provide a good flowing ability in SCC. In addition, the HRWRs deflocculated the cement particles and free the trapped water by their dispersing action, and hence enhance the flowing ability of SCC. In dispersing action, the inter-particle friction and thus the flow resistance are also decreased, and therefore the flowing ability of concrete is improved. High-range water reducers can either increase the strength by lowering the quantity of mixing water for a given flowing ability, or reduce both cement and water contents to achieve a given strength and flowing ability. They contribute to
Read more

marsh cone test for passing ability of mortar

Image
marsh cone test for passing ability of mortar As per thesis methodology the optimum content of super plasticizer was found out by marsh cone test for different water powder ratio. The Marsh funnel is a apparatus shown in figure below use to find out the viscosity of the fluid to pass out from nozzle shown below by measuring time for known volume of the paste. For water cement ratio 0.40 proportion mix was taken as 90% cement and 10% RHA was thoroughly mix. The slurry was made by the use of mortar mixer and 0.5 to 2% super plasticizer was added by weight. For the test slurry of 10% RHA blended with the cement and mixes homogeneously with the hand. The mixture is filled in in the mortar mixture pan as shown in figure required water is to be added as per decide water cement ratio and super plasticizer in different percentage. The slurry was screened by the 2.36 mm sieve. And filled the cone till its top level during this bottom whole should be block by finger. Set stop
Read more