I am going to use the polymer slurry to stablise the bore of 1.5m diameter piles, for a major bridge project in India. Can any one give me the following informations regarding polymer slurry :
a) What are the benefits of using the polymer slurry as against the conventional 'Bentonite Slurry'. b) What 'precautiona' & 'checks' are necessary at site for ensuring correct and appropriate use of polymer slurry. c) Is there any reduction in skin frictional capacity of bored piles, if polymer slurry is used?
a) The benefits of working with polymer slurry is that 1) you do not have to desand your slurry before concreting which is only interesting when your schedule of works is asking for more than 2 piles concreted per day. 2) if bentonite is not readily available, you will not have to transport as much material with polymer than with bentonite ( 30 times less roughly )
b) a polymer slurry must be treted exactly the same way than a bentonite slurry. You should work with a propduct which has a good list of references ( personnally I have always used GSTP from JF TECH ). You should not use polymer slurry in very permeable soils ( clean gravel for example ) If you are in sandy soils you might have to add some bentonite ( a few Kg per m3 ) to help the formation of the cake. You will have to make sure that you have the necessary equipment to revert to bentonite mud if necessary. Once the excavation of the pile is completed you should wait half an hour to allow for the soil particles in suspension in the slurry to sediment and then clean the bottom of the hole. c) no, on the contrary, sometimes tension piles are specified to be drilled under polymer slurry. I believe there is no difference one way or another