For reinforcing, asphalt mastics are used as grouts to fill and plug 

 the voids in stone structures such as jetties and revetments (Figs. 44 and 

 45) . The binding action of the mastic tends to make one firm mass, yet 

 mastics are flexible enough to conform to some differential settlement in 

 the structure. Asphalt mastics are also used as joint fillers to bind stone 

 blocks together on coastal structures, particularly in European construc- 

 tion. 



2.4 m (8 ft) 



ASPHALT CONCRETE CAP 



ASPHALT SEAL (GROUTING) 

 COURSE 



COVER STONE 

 5.4 to 9.1 1 (6 TO 10 



TONS) 



CORE STONE 



34 kg to 1 .8 1 



(75 LB. TO 



2 TONS) 



0.9 m (3 ft) 



RIPRAP 7 to 91 kg (15 to 200 LB.) 



Figure 44. Cross section, south jetty, Galveston, Texas. 



(5) Surface Treatments . 



(a) Purposes . A surface treatment may be applied to an 

 asphalt surface for a number of reasons. It may be designed to make the 

 surface more watertight, or to protect it from abrasion by waves, water 

 currents, or even by ice. A layer of mud deposited on an asphalt surface 

 or algae and other sediments, and allowed to dry, will shrink as they dry 

 will set up suprisingly large tensile stresses at the surface resulting in 

 the surface curling or cracking. A surface treatment may also be used to 

 protect the surface from mud curl or the curling of drying algae along the 

 waterline, to give the surface a lighter color in order to reduce tempera- 

 ture extremes, or to reduce the rate of oxidation of the exposed asphalt 

 surface. 



(b) Sprayed Asphalt Seals . Asphalt cement or emulsified 

 asphalt sprayed over the surface of an asphalt lining at the rate of 1 

 liter per square meter (0.25 gallon per square yard} will provide a film 

 coating as much as 1 millimeter (0.04 inch) thick. A continuous film 

 coating will fill and seal any exposed pores and increase the watertightness 

 of the asphalt lining. It will also tend to fill and seal small cracks in 

 the surface that may have been caused by improper rolling procedures in 

 compacting the lining. The surface should be clean, dry, and free from 



179 



