Low traffic volume highways are ideal for carrying out experiments with local materials once their application for subbases and subgrading has been tested with pertinent experiments. If these local materials exist in large quantities and were to represent an environmental problem, then their use would be doubly justified. Using flying ashes from coal-thermal power plants for manufacturing these road subbases is not new in some countries, but in Spain, there is no reference to their being used for highways except those mentioned in this paper. In addition to being a novelty on a national level, the use of unofficially approved aggregate in the ash and lime mixtures should be mentioned: these aggregates, of a local nature and of volcanic origin, do not comply with certain standard specifications with regard to density, California bearing Ratio test, and granulometry, but have yielded excellent results in the works carried out, which makes them twice as valuable because of the savings involved to extract them and the ease of repaying the loan used for the extraction. Experiments carried out have focused on the Puertollano region (Ciudad Real), using residual ashes from the Eneco thermal power plant with deposits of millions of m3 in the area. Some of the sections of highway built will bear T2 traffic. The sand and cement were extracted from small volcanic formations near the construction. (A)
Abstract