Abstract

Building influenes of highways and by-pass roads as well as fast roads modernization strongly the natural environment. Keeping of slopes situated along these structures in good condition requires a biological reinforcement and a cover with grass and papilionaceous plants. That is why American research workers, who have been interested in this problem for 40 years, have invented mulching, hydromulching and hydroseeding technology. This method is currently used almost all over the world. In Poland the hydroseeding has been involved 20 years ago. However taking into account the program of highway and by-pass roads development, we should implement this method on a large scale. Technical meaning of the word "slope" assigns significantly inclined area which joins two horizontal or almost horizontal surfaces lying on different heights. In this meaning, slope replaces and acts as a resistance wall. The slopes protect embankments and excavations, reinforce drainage ditches and regular river-beds. The slope is a construction element of earthen structures. Slope concern not only inclined areas of soil but also adherent horizontal strips of suitable width at road crown and toe. The problem of biological reinforcement (grassing) of uncovered, inclined surfaces of anthropogenic earthen structures was discussed. The studies were undertaken to protect the natural environment against harmful effects of water/soil erosion occuring on such surfaces. A main component of sowing hydromixtures was a sewage sludge from municipal treatment plant. The sludge form a medium/binding agent for antierosive protective coats, since a moment of their hydromechanical spreading on the surface of tested anthropogenic soils, until developing of the third full-blown grass leaf. The investigations concerning rain-washes were conducted under laboratory (repeatable) conditions, where formation and shaping of water erosion processes were simulated. Sloped areas (14-45°) of anthropogenic structures from natural soils (medium sand) and anthropogenic soils (fly-ash) were tested.