If the asphalt mixture travels freely through the water over 

 a certain distance or is exposed to wave action while it is being 

 poured, the mixture will change into a porous mass which hardly 

 penetrates at all, with unreliable "work as a result. It has been 

 found that in poor mixture which are submerged permanently or 

 regularly, the film of asphaltic bitumen which covers the particles 

 is gradually replaced by water , causing the mixture to lose its co- 

 herence and fall apart , Since it is impossible to coat the wet layer 

 of porous material with an impermeable layer of asphaltic bitumen 

 or tar, it is recommended that a sufficiently rich mixture be 

 chosen initially for layers which are constantly or regularly sub- 

 merged by water o 



In the following description of works executed with the use 

 of hot asphalt, the above-mentioned points will further be dis- 

 cussed where necessary „ 



Works Executed with the Use of Hot Asphalt 



Since hot asphalt has been used in a great many hydraulic works, 

 it is impossible to give a complete record in this short review. 

 Therefore only a description of a number of applications will be 

 given for the following constructions, 



1,, bank protection along canals 



2. impermeable sheeting of the wetted profile of canals 



3» impermeable sheeting of weirs 



4-. bank protection along rivers 



5. slope protection along sea shores 



60 mattresses 



7. reinforcement of beach groins and harbour-dams. 



The original translation contained discussions of the first 

 four types of works; these have been deleted in this presentation. 



Slope Protection Along the Sea-shore 



The following applications of asphaltic bitumen or asphalt 

 mixtures have been made. 



Trial Section on the Outer Slope of the "Northeast Polder" Dike 

 Near Urk 1936 



At this trial section (total area of 2000 m^) tests were 

 made In cooperation with and under control of the Research Lab- 

 oratory of the Royal Shell at Amsterdam. The slope of the dike 

 ranged from 1°.A at the bottom to 1?3 at the top, separated by a 

 5 m terrace at about 2.00 m + N.A.P. (Normal Amsterdam Level). 



Test la. Penetration of macadam with pure asphaltic bitu- 

 men. The area extends from +2.00 to +3° 50 m (Normal 

 Amsterdam Level) and is covered respectively by a layer 

 of set bricks, an 8 cm layer of dumped rubble stone 

 and an 8 cm layer of compacted broken stones of 3-5 

 cm. This last layer was penetrated with 9 kg/m^ 



