Hugh Nibley cites Peter Thompkins, who quotes Katherwood about the mortar that was used at Labna, where the beautiful gate is and quite a bit of highway. These ancient highways are way up in Yucatan, not down in South America. Labna has a beautiful ceremonial gate and a highway leading to it. But there is lots of concrete used, and it was analyzed. Katherwood found that it was the very same mortar that was used in Puzaawoelana by the Romans with such effect in building with concrete. But there's a more recent study in the August 1980 National Geographic (page 216), quoting S.J.K. Wilkerson. He says, "In the use of poured concrete, says my engineer colleague David Hyman, El Tajin's builders excelled at a technique remarkably similar to today's." So it wasn't just mortar between bricks or stones; it was poured concrete. When they say it was cement, it was real cement--which comes as a surprise. [Hugh W. Nibley, Teachings of the Book of Mormon, Semester 4, p. 238]
“Expert in the Working of Cement Houses of Cement”
According to Helaman 3:7, the people who went into the lands northward became "expert in the working of cement" and built "houses of cement." According to David Palmer, the use of cement and concrete spread throughout Mesoamerica in a time span from at least as early as 100 B.C. through A.D. 400. The tourist sees it in great abundance at Teotihuacan (near Mexico City). At Kaminaljuyu (Guatemala City) the concrete mix was similar. Tiny pieces of volcanic stone, 0.5 to 2 millimeters in diameter, were mixed with clay and lime. After drying, a very smooth and durable surface is formed. An early manifestation of the use of cement is at Chiapa de Corzo, Chiapas where it was used to surface the temple known as Mound 1. This can also be seen at Monte Alban (Oaxaca).
The knowledge of this use of cement in Mesoamerica has not been around for many decades. In 1929, Heber J. Grant, a former president of The Church of Jesus Christ of Latter-day Saints, made the following statement in general conference:
. . . I have often said, and desire to repeat here that when I was a young unmarried man, another young man who had received a doctor's degree ridiculed me for believing in the Book of Mormon. He said he could point out two lies in that book. One was that the people had built their homes out of cement and that they were very skillful in the use of cement. He said there had never been found and never would be found a house built of cement by the ancient inhabitants of this country, because the people in that early age knew nothing about cement. He said that should be enough to make one disbelieve the book. I said: "That does not affect my faith one particle. I read the Book of Mormon prayerfully and supplicated God for a testimony in my heart and soul of the divinity of it, and I have accepted it and believe it with all my heart." I also said to him, "If my children do not find cement houses, I expect that my grandchildren will." He said, "Well, what is the good of talking with a fool like that?" (April 1929 Conference Reports, p. 128ff).
The documentation of use of cement in Mesoamerica is now so overwhelming and obvious that President Grant's statement stands out as prophecy now fulfilled. [David A. Palmer, In Search of Cumorah, pp. 121-122]
Helaman 3:7 Expert in the working of cement: [Cement] used to surface the temple at Chiapa de Corzo now known as Mound 1. [David A. Palmer, In Search of Cumorah, p. 121]