MANUAL 4 - Construction Industry Development Board

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<strong>MANUAL</strong> 4 – BITUMINOUS PAVEMENT SEALS Photo 4.19 • Add the cement to the aggregate in the drum very slowly (Photo 4.20), making sure no lumps or clods of cement are added (or make a cement slurry before adding to mix). Photo 4.20 • The mix must be inspected to ensure the uniform distribution of the cement in the aggregate, before any emulsion is added. Notes 1. The cement must be added to the neat aggregate and no attempt must be made to add the dry cement after the emulsion has been added. 2. If, for any reason, extra cement needs to be added, it must be added as a slurry of water and cement mixture. IMPLEMENTING EMPLOYMENT INTENSIVE ROAD WORKS 43 MODULE 1 2 3 4 5 6 7
MODULE 1 2 3 4 5 6 7 <strong>MANUAL</strong> 4 – BITUMINOUS PAVEMENT SEALS When drums of emulsion have been stored for any length of time, the bitumen molecules in the emulsion tend to settle to the bottom of the drum. Therefore, it is essential to roll the drum and mix the contents well before use. It is even recommended that the day before the drums are to be used, they are turned upside down before being rolled for the next day’s use. It is recommended that full drums are stored not vertically but horizontally, ready for rolling and mixing and empty drums are stored vertically – apart from mixing by rolling the drums, it facilitates stocktaking. • The diluted emulsion must be poured slowly into the mixer and not dumped into the mixer (Photo 4.21). By slowly pouring fluid into the mixer, quicker and more efficient coating of the aggregate will occur, without spillage or splashing of both the emulsion and the slurry. The drum of the mixer must not be in the vertical position when pouring the emulsion. This vertical position is used by the operator to protect him from splash, caused by the dumping of emulsion into the drum. Note that the drum must be just off the horizontal position, and that the emulsion should be poured slowly, deep into the throat of the drum, resulting in very little splash. Pour a little at a time and allow mixing before the next pour is done. Photo 4.21 • Before adding the water, inspect the mix as it may not need much water to get the correct consistency. Carefully add the water in 2,5 litre amounts (Photo 4.22), and allow thorough mixing before adding further water. IMPLEMENTING EMPLOYMENT INTENSIVE ROAD WORKS 44
Page 1 and 2: Implementing employment intensive r
Page 3 and 4: Implementing employment intensive r
Page 5 and 6: Overview of the practice manuals Th
Page 7 and 8: MANUAL 4: Bituminous pavement seals
Page 9 and 10: MODULE 1 2 3 4 5 6 7 MANUAL 4 - BIT
Page 13 and 14: MODULE 1 2 3 4 5 6 7 Note Do not ta
Page 35 and 36: MODULE 1 2 3 4 5 6 7 Rate of binder
Page 39 and 40: MODULE 1 2 3 4 5 6 7 6 MANUAL 4 - B
Page 41: MODULE 1 2 3 4 5 6 7 Typical spread
Page 47 and 48: MODULE 1 2 3 4 5 5.1 5.2 MANUAL 4 -
Page 59 and 60: MODULE 1 2 3 4 5 6 7 Slurry seal wo
Page 69 and 70: MODULE 1 2 3 4 5 6 7 Rate of binder
Page 79 and 80: MODULE 1 2 3 4 5 6 7 Note MANUAL 4
Page 91 and 92: eferences The framework agreement f
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MANUAL 4 - Construction Industry Development Board

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