Bulletin-28—Pumice Aggregate in New Mexico—Uses and Potentialities

By D. M. Clippinger and W. E. Gay, 1947, 50 pp., 8 figs., 18 plates, 1 index. Supplement to Bulletin 24.

As a result of the acceptance of pumice as a highly desirable and advantageous natural lightweight concrete aggregate, a new industry is being rapidly developed. Recent activities in the field of construction show that this new resource is adding greatly to the wealth and welfare of NM. The state has sufficient pumice to supply for decades to come, the aggregate needs (at the present rate of building) of all plants producing concrete and concrete products in NM, TX, CO, OK, KS, NE, MO, and IA. These states comprise the large region within which pumice can be shipped by rail and still remain well within competitive range.

The purpose of this bulletin is to describe and discuss the uses and favorable characteristics of pumice, especially in construction. Data have been compiled from reliable sources concerning the successful uses of pumice aggregate and the physical properties of pumice products. Experiments have also been conducted using generally accepted particle distribution and concrete-mix designs. Graphs and charts comparing the physical properties of pumice with those of other building materials are presented. Special emphasis is placed on the importance of proper control in mining and grading operations, to produce a satisfactory and marketable aggregate. The general application for building use is outlined, as well as agricultural applications and possibilities. Studies have been made of the economics of pumice concrete. The past and present production has been surveyed as an aid in predicting future demand. This report supplements Bulletin 24 of this series, which is devoted to all natural lightweight building materials in general.

Pumice was used in Rome over 2,000 years ago in the construction of the great dome of the Pantheon, the immense vaults of the public baths, and other notable structures. The matrix of cementitous material employed was composed basically of pumicite. Pumice as a concrete aggregate has been used in Germany since about 1850, and still holds a principal position in the building industry there. From New Zealand, Japan, and other countries where suitable pumice occurs in quantity, good reports have been received on its use for building purposes. However, little research work has been performed until recent years. The information now available is conclusive enough to provide the architect and engineer with strength values in compression, flexure, tension, shear, bond, unit weight, thermal conductivity, coefficient of heat transmission, thermal coefficient of expansion, fire resistance, modulus of elasticity, sound absorption, and resistance to condensation.