In 3 Nephi 6:8 it says that "there were many highways cast up, and many roads made, which led from city to city, and from land to land, and from place to place."
According to Joy Osborn, in 1824, six years before the Book of Mormon was published, Joseph Aspdin had patented a process for making portland cement. About this same time John McAdam, in Scotland, had developed the road surface finish still known today as "macadam."
Willard, in The City of the Sacred Well, said of their ancient cement roads:
Several thousand of years before the sturdy Scotch engineer John McAdam gave to the world the broken-rock road surface known as "macadam" which has done so much to make communication easier, roads were built in Yucatan that embodied all his sound principles of road-making. And McAdam lived and died without ever having heard of them. In fact, he had been sleeping beneath the green sod of his native kinfolk at least a decade before Europe or North America knew that these old roads of Yucatan existed. The thoroughness and good engineering of their construction rival the famous roads of the Roman Empire or of present-day highways. The old roads, each and every one, went down to bedrock, and upon that solid foundation was built up a ballast of broken limestone, with the larger stones at the bottom. As the surface of the road was reached, smaller stones were used and the crevices were filled in. The whole face of the road was given a smooth, hard coating of mortar cement of lime and finely sifted white earth, known then and today as zac-cab. (pp. 88-89)
[Joy M. Osborn, The Book of Mormon -- The Stick of Joseph, pp. 149-151] [See the commentary on Helaman 7:10]
“There Were Many Highways Cast Up and Many Roads Made”
There are numerous references to highways in the Book of Mormon. One example is in 3 Nephi 6:8 where it says that "there were many highways cast up, and many roads made." According to Glenn Scott (and assuming a Mesoamerican setting), these roads were topped with a lime cement called sascab that hardened under wetting and pressure. Maya highways were called sacbe (plural sacbe ob) which according to Sylvanus Morley, meant built-up roads (sac = made-by-hand, be = road). Paul Cheesman offers another interpretation. He says sac means white because of the white material called sascab with which the Maya surfaced those roads (Cheesman and Hutchins 1984, Pathways to the Past, 101). Support for the latter definition comes from Victor von Hagen, who wrote, "On top went a limestone gravel, which when wetted and tamped down, made a hard smooth surface. The result was the white road."
T.A. Willard recorded, "The whole face of the road was given a smooth hard coating of mortar cement of lime and finely sifted white earth, known then and today as zac-cab" The bottom layer consisted of large boulders. Chinks were filled with small stones hammered into place. The second and third courses were of smaller stones carefully placed. The top layer was fragments pounded level and bound together with a cement grout. The surface was paved with a two-inch layer of lime cement rubbed smooth. In swampy areas (bajos) native engineers made sure the foundation was deep and firm. There were no detours to avoid bajos. [Glenn A. Scott, Voices from the Dust, pp. 190-191]
3 Nephi 6:8 There were [many highways] cast up, and many roads made: Maya Highways A schematic map of Maya sacbe ob (highways) which have been identified. (per Victor von Hagen - 1960) [Glenn A. Scott, Voices from the Dust, p. 192]