GB1035879A - Asphalt lining - Google Patents

Abstract

An asphalt composite lining for use in lining ditches and the like, comprises a central non cracking flexible asphalt composition layer, an upper intermediate layer of reinforcing material impregnated with asphalt and bonded to the upper side of the side of the central composition layer, an upper coating layer of asphalt adjacent to the upper intermediate layer and bonded thereto to render the upper intermediate layer non curling and non-shrinking under weathering conditions, a lower intermediate layer of reinforcing material impregnated with asphalt and bonded to the lower side of the central composition layer, and a lower intermediate layer and bonded thereto to render the lower intermediate layer non-curling and non-shrinking under weathering conditions, the central asphalt composition layer containing asphalt and fillers mixed therewith wherein the asphalt in the central layer is present in an amount from 40 to 80% and the fillers are present in an amount from 60 to 20%. The central asphalt composition layer may contain 70% of asphalt, 20% mineral fillers e.g. slate flour, limestone, talc, and silica, mica, sawdust, rice hulls, peanut hulls and cork, and 10% fibrous material e.g. ground, shredded, pulverized or sheet felt, whereby the fibrous material and mineral filler are present in the central layer in amounts sufficient to provide the final composite lining such that a four inch square sample thereof shows no deflection from a horizontal position when subjected to 150 DEG F for two hours, and which also shows no flow when placed on a 45 degrees angle is subjected to 200 DEG F for one hour, and which does not crack or shatter when subjected to the impact of one pound steel ball dropped from a distance of three feet at 0 DEG F, the asphalt in the asphalt composition layer and in the coating layers having a melting point (ball and ring) of 140 DEG to 220 DEG F, and a penetration (defined) at 77 DEG F of 90 to 10mm x 10-1, and the asphalt lining is substantially uniformly non-curling, non-cracking and pliable under sustained weathering and over a temperature range from freezing to 200 DEG F. The reinforcing material may consist of paper e.g. kraft paper, felt, metal wire, glass fabric or glass gauze. The central layer may have a stiffener layer, e.g. of plastic or fibreglass, centrally embedded therein. The asphalt lining may be installed in a reservoir, irrigation ditches, canals or the like by compacting the soil, providing drainage channels in the soil for the removal of fluid from beneath the lining when installed, and thereafter installing the lining in sheets or strips over the channels. Gravel and/or porous pipe may be placed in the channels prior to installing the lining thereover. Abutting sheets of the lining may be joined with asphalt sealing material. The sheets may also be laid in overlapping relationship. An oil-insoluble light-reflective point may be applied to the exposed surface of the lining.