Cold paving is road construction using cold mixtures which, like hot mixtures, may have various bituminous materials and aggregate gradings. Bitumen emulsion is the key component of cold mix-technology, because it is fluid enough to allow mixing with aggregates without heating and drying. Cold mixtures are already being used extensively in various parts of the world. The advantages of cold paving over traditional hot mix can be classified into three areas: (1) energy savings; (2) reduced capital costs; and (3) safety and environmental considerations. It is estimated that the energy to construct a road, using solvent-free cold-mixed materials on a granular sub-base, is about 40% of the energy to construct an equivalent road from hot-mixed materials. The energy savings are especially important when hot-mix plants are remote and cold-mix plants can be located near the job site or a source of local aggregates. Hot-mix plants are more costly than cold-mix plants, because of the needs to heat and dry the aggregate, store the hot mix, and control the emission of fumes and dust. The perceived environmental and safety advantages of cold mix, other than energy savings, have not usually been a major factor in using cold mix. The article finally discusses the use of cold paving in Bolivia.
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