GB573741A - Improvements in or relating to bituminous compositions containing mineral aggregates - Google Patents

Abstract

Bituminous compositions are prepared by adding up to 6.5 per cent of water to a mineral aggregate of the kind which becomes at least feebly cemented to a coherent mass when wet, and mixing the product with 3-8 per cent of the weight of the aggregate of a non-dispersed bituminous binder which may or may not wet the aggregate in the presence of water, at a temperature less than 100 DEG C., the proportion of water in the finished composition being at least 3 per cent of the weight of the aggregate. Examples of aggregates are natural sand or gravel containing clay or clean sand, gravel or the like to which has been added calcium hydroxide, magnesium oxide, Portland cement, ferric oxide, or clays of the montmorillonite type. Fillers such as china clay, slate dust, precipitated chalk and limestone dust activated by an addition of calcium hydroxide can also be used. Bituminous binders, which may be cutbacks, may be petroleum asphalts, residual oils, mixtures of asphalts or oils with petroleum or coal-tar distillates, coal tars, pitches, or mixtures thereof with coal-tar distillates, and additives to encourage wetting of the aggregate by the binder may be added. Preferably from 4 to 6 per cent of water is used, but allowance for evaporation must be made when mixing is carried out at high temperatures. According to the Provisional Specification, the binder may be added in the form of an aqueous dispersion.