Innovative and Sustainable Uses of Volcanic Ash as a Natural Pozzolan for Dust Abatement and Unpaved Roadway Improvement

Natural pozzolans are supplementary cementitious materials that, when used in the presence of materials with the correct chemistry, can produce a cementitious reaction. Common natural pozzolans include industrial by-products such as fly ash, calcined clay, and kiln dust, among others. The benefits of natural pozzolans in Portland cement concrete mix design are well known. The objective of this research is to determine the suitability of using a naturally occurring pozzolan, namely volcanic ash from the eruption of Mt. Mazama, for benefits such as dust abatement and unpaved roadway improvement. Mt. Mazama volcanic ash is plentiful at the ground surface in South-Central Oregon. If shown that Mt. Mazama volcanic ash has beneficial uses, and can replace Portland cement in some applications, there are potential economic and sustainability benefits for the region. This research documents the natural pozzolanic ability of the Mt. Mazama volcanic ash according to ASTM standards. A laboratory program was also carried out to determine the maximum proportions of volcanic ash in a Portland cement concrete mix design that would still produce a cementitious reaction. The laboratory program included innovative dust abatement tests and unpaved roadway penetration tests to determine if the sustainable, volcanic ash could be beneficial. Tests indicate that volcanic ash may prevent the formation of dust on unpaved roadways and may be used as a topically applied binder to loose, unpaved roads.