New World Cements

Available literary and photographic evidence strongly suggests that hydraulic cements were manufactured and utilized in Mexico and Central America more than a thousand years before Old World civilization produced portland cement. A material much of the same as present day concreate had been poured in the Valley of Mexico two or three centuries B.C.E. (Dumas, 1961, Tome-1, p. 403). No less an observer than Humboldt found hard mortar as far afield as Pullal and Cunmas in northern Peru (Henry Reid, 1879, p. 8). Examples of "lime mortar" abound in ancient sites in Yucatan and ". . . one-sixteenth of most Maya structures are lime mortar," (Von Hagan, 1962, chapter 30).

Photographs (Robertson, 1963) offer evidence of existing rubble stone walls which could not have remained standing unless they contained mortar made with hydraulic cement (Robertson, 1963, plates 27, 28, 40, 41, 46 & 52). This type of wall depends upon great structural strength in the mortar, for the stones are irregular and not flat bed cut as is ashlar. Furthermore, sections through the Maya Temple indicate a construction similar to Roman (or for that matter, to modern) concrete building techniques (Robertson, 1963, plates 53, 54 & 75).

Unfortunately, these photographs and sections (Robertson, 1963) as well as similar pictures and diagrams from other sources are grossly misleading. Seen in the field, the bulk of mortar bound rubble masonry is either colonial or modern reconstruction. The cross sectional views, while correct in profile, are schematic with regard to the placement and shape of the masonry units to the point of misrepresentation. These sections led to the mistaken impression that these buildings would be none other than faced matrix bound concrete structures. Viewed in situ the actual quasi-arches were in fact constructed of corbelled unit masonry (See Chapter 6. Conclusions).

The incorrectly detailed cross sections published in Robertson's plate No. 54 are precisely the same as those appearing in Morley's, The Ancient Maya, Fig. 34. Even more schematic but quite similar are the first four corbelled vault diagrams in I11. 39 of Bushnell's The First Americans. Apparently all of these, were derived from a single incorrect source.