Silt Factor


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Softening point IS 1205 1978

Hot the bitumen in oven or on hot plate at 75oc – 110oc above softening point say at 90oc + softening point of bitumen and pour it in the rings Balls weights 3.5 gms and dia of Ball is 9.5 mm After 30 min in air place it in beaker 600 ml and keep it in apparatus the temp of Distilled water should be 0oc and heat it at the rate of 5oc /min place the thermometer and note down the temp when balls touched the lower plate. For CRMB 55 the Softening point is 55oc For CRMB 50 the softening point is 50oc And For CRMB 60 the Softening point is 60oc For Bitumen having the Softening point above 80oc use Glysrine in place of water and the starting temp should be 35oc In IS 1205 1978 the water bath is written to perfotm the test first keep the beaker with sample in water bath for 15 min at 5oc and then allow to rise the temp at 5oc per min.
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Stripping value

Take the sample passing 25 mm and retaind on 12.5 mm IS sieve. Heat the aggregate at 150oc and Binder at 160oc and then mix it according to yhe percentage then allow it to cool for 2 hours Put the mix in beaker with Distilled water.Then place it in water bath for 24 hours at temp of 40oc and cover the beaker with glass sheet or any other suitable device. After 24 hours saa the stripping visually while specimen in beaker with water not touching the specimen. As results cames the antistripping agent will required for according to percentage of stripping. The Stripping value depends on the nature of aggregates.as the water absorbption is more stripping is more and if the aggregates are with smooth surface the stripping will be more. As specific gravity is more the stripping is less. Secondly use the Distilled water to perform the test.If we use normal water the salts present in water will give more stripping.
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Joints in concrete 456/IRC 58

Concrete joints are provided to compensate thermal expansion and contraction. The structural separation of concrete members to allow independent movement without damage. They are designed to absorb thermal expansion of concrete. They are commonly provided in bridges, slabs, railways. Bitumen Fibre Board, Dura Board Normally structures exceeding 45 m in length are designed with one or more expansion joints. The pre planned cutting grooves are given in concrete where occurrence of cracks are expected. The depth of groove is 25% of total thickness of the concrete member. Grooves are given in a straight line. These are due to shrinkage or temperature variations. Cutting grooves with blade. Providing glass strips panels not exceeding 3 sqm area in flooring When the work cannot be completed in a single day, construction joints are provided in concrete. These are common in big rafts, beams where joint is provided at L/3 Nito bond, Sika latex,Bitumen Fibre Board, Dura Board
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