Under the generic name of high modulus bituminous mixtures, there is a series of special agglomerates with a strong structural capacity. High modulus bituminous mixtures for base courses and reinforcements are characterized by their high rigidity modulus (2 to 3 times that of standard mixtures), a resistance to fatigue that is normally enhanced by these mixtures, and a great resistance to plastic deformation. This is possible because they are prepared with continuous grading crushed stone aggregates that provide a good mineral coarse aggregate and with a high content of special pitch with minimal penetration. Their high regidity modulus (greater than 14 000 MPa at 15 C and 10 Hz) and high resistance to fatigue allow for thinner base course or reinforcement designs. According to the characteristics of the other roadbeds, reductions in thickness may reach up to 30%. Above and beyond reduced thickness and economy, high modulus mixtures offer other advantages such as absence of cracks due to thermal shrinkage, great impermeability, uniformity of layers, etc. In our country, the first experiments with this type of mixtures date back to 1992. Today, some 100 000 tons are manufactured, and although the limited time span does not permit us to draw any definitive conclusions regarding their performance, results so far are promising. This presentation briefly describes the composition of these mixtures, their dosage in the laboratory, fundamental characteristics, manufacturing and use. Examples provided include different structural alternatives where this type of mixture is applied to different standard sections from the Spanish sections catalogue. In conclusion, we present the experience Probisa had with high modulus emulsion gravel in successfully combining the advantages of cold-bituminous mixture techniques with high modulus. (A)
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