Image by Ben­jaminec, via Wiki­me­dia Com­mons

Rome may not have been built in a day, but it was built to last — or at least its con­crete was, giv­en that the pieces of the Roman Empire that have stood to our time, in one form or anoth­er, tend to have been built with it. That mate­r­i­al has proven not just durable but endur­ing­ly fas­ci­nat­ing, hold­ing a great deal of not just his­tor­i­cal inter­est but tech­ni­cal inter­est as well. For ancient Roman con­crete appears to out­last its much more tech­ni­cal­ly advanced mod­ern descen­dants, and the com­plex ques­tion of why is one we’ve fea­tured more than once here on Open Cul­ture. Just this year, researchers at MIT, Har­vard, and lab­o­ra­to­ries in Italy and Switzer­land have found what seems to be the final piece of the puz­zle.

“For many years, researchers have assumed that the key to the ancient concrete’s dura­bil­i­ty was based on one ingre­di­ent: poz­zolan­ic mate­r­i­al such as vol­canic ash from the area of Poz­zuoli, on the Bay of Naples,” writes MIT News’ David L. Chan­dler. “Under clos­er exam­i­na­tion, these ancient sam­ples also con­tain small, dis­tinc­tive, mil­lime­ter-scale bright white min­er­al fea­tures.”

Pre­vi­ous­ly assumed to be noth­ing but imper­fec­tions in the process or the mate­ri­als, these “lime clasts,” in light of this most recent research, con­sti­tute evi­dence of “hot mix­ing,” which involves heat­ing to a high tem­per­a­ture ingre­di­ents includ­ing quick­lime (or cal­ci­um oxide), a pur­er and more reac­tive form of lime.

Under­go­ing hot mix­ing, “the lime clasts devel­op a char­ac­ter­is­ti­cal­ly brit­tle nanopar­tic­u­late archi­tec­ture, cre­at­ing an eas­i­ly frac­tured and reac­tive cal­ci­um source” that “could pro­vide a crit­i­cal self-heal­ing func­tion­al­i­ty.” In prac­tice, this means that “as soon as tiny cracks start to form with­in the con­crete, they can pref­er­en­tial­ly trav­el through the high-sur­face-area lime clasts. This mate­r­i­al can then react with water, cre­at­ing a cal­ci­um-sat­u­rat­ed solu­tion, which can recrys­tal­lize as cal­ci­um car­bon­ate and quick­ly fill the crack, or react with poz­zolan­ic mate­ri­als to fur­ther strength­en the com­pos­ite mate­r­i­al.” Here we have a con­vinc­ing expla­na­tion of the reac­tions that, in ancient Roman con­crete, “auto­mat­i­cal­ly heal the cracks before they spread.”

No such self-heal­ing hap­pens in mod­ern con­crete, the pro­duc­tion of which has not involved quick­lime for a very long time indeed — but per­haps it could once more. Dur­ing their research process, writes Dezeen’s Rima Sabi­na Aouf, the team “pro­duced sam­ples of hot-mixed con­crete using both ancient and mod­ern for­mu­la­tions, cracked them, and ran water through the cracks. With­in two weeks, the cracks had healed and water could no longer flow through, while iden­ti­cal con­crete blocks made with­out quick­lime nev­er healed.” Such find­ings “could help increase the lifes­pan of mod­ern con­crete and there­fore mit­i­gate the noto­ri­ous envi­ron­men­tal impact of the mate­r­i­al,” and the researchers “are now work­ing to com­mer­cial­ize their more durable con­crete for­mu­la.” Even in the twen­ty-first cen­tu­ry, the build­ing indus­try could well ben­e­fit by doing as the Romans did.

via MIT News

Relat­ed Con­tent:

How Did the Romans Make Con­crete That Lasts Longer Than Mod­ern Con­crete? The Mys­tery Final­ly Solved

How to Make Roman Con­crete, One of Human Civilization’s Longest-Last­ing Build­ing Mate­ri­als

How Did Roman Aque­ducts Work?: The Most Impres­sive Achieve­ment of Ancient Rome’s Infra­struc­ture, Explained

How the Ancient Romans Built Their Roads, the Life­lines of Their Vast Empire

The Beau­ty & Inge­nu­ity of the Pan­theon, Ancient Rome’s Best-Pre­served Mon­u­ment: An Intro­duc­tion

Roman Archi­tec­ture: A Free Course from Yale

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities, the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les and the video series The City in Cin­e­ma. Fol­low him on Twit­ter at @colinmarshall or on Face­book.

If we seek to under­stand West­ern civ­i­liza­tion, we must look back not just to Rome, but also to Athens. And today, thanks to com­put­er-gen­er­at­ed imagery informed by his­tor­i­cal research, we can look not just to those cities, but at them — or at least at con­vinc­ing dig­i­tal recon­struc­tions, but from angles their actu­al inhab­i­tants could scarce­ly have imag­ined. A few years ago, we fea­tured here on Open Cul­ture the Youtube chan­nel Ancient Athens 3D for its recon­struc­tions of indi­vid­ual struc­tures like the Tem­ples of Ilis­sos and Hep­haes­tus. Its more recent video above offers a twelve-minute vir­tu­al tour of all clas­si­cal Athens in the fifth cen­tu­ry BC, the height of ancient Greek civ­i­liza­tion.

In that peri­od, accord­ing to the video, Athens “was the cen­ter of the arts, the­ater, phi­los­o­phy, and democ­ra­cy.” In the city “great mon­u­ments of archi­tec­ture were built and were large­ly asso­ci­at­ed with the Athen­ian gen­er­al Per­i­cles.”

It was Per­i­cles who led the city-state dur­ing the first two years of the Pelo­pon­nesian War, the con­flict in which Athens would even­tu­al­ly fall to Spar­ta in 404 BC — a defeat that had almost, but not quite come to the city at the moment Ancient Athens 3D cre­ator Dim­itris Tsalka­nis brings it back to life. He includes every­thing from the Acrop­o­lis and the Ago­ra to the Olympieion and the Sacred Gate, all look­ing as if they’ll stand for­ev­er.

Nor does Tsalka­nis ignore even bet­ter-known clas­si­cal Greek build­ings like the Parthenon, whose detailed recon­struc­tion, inside and out, also appears in its own video just above. Com­mis­sioned by Per­i­cles, built on the Acrop­o­lis, and ded­i­cat­ed to the god­dess Athena, “patroness of the city of Athens,” the build­ing remains “a sym­bol of ancient Greece, democ­ra­cy, and West­ern civ­i­liza­tion” near­ly two and half mil­len­nia after its con­struc­tion, and more than two cen­turies after the Earl of Elgin had its mythol­o­gy-depict­ing mar­bles sent off to Eng­land. You can still see them at the British Muse­um (at least for now), and for that mat­ter you can still vis­it the Parthenon itself in Athens — or at least the ruins there­of, whol­ly untouched by dig­i­tal mag­ic.

Relat­ed con­tent:

Explore Ancient Athens 3D, a Dig­i­tal Recon­struc­tion of the Greek City-State at the Height of Its Influ­ence

What Ancient Greece Real­ly Looked Like: See Recon­struc­tions of the Tem­ple of Hadri­an, Curetes Street & the Foun­tain of Tra­jan

How Ancient Greek Stat­ues Real­ly Looked: Research Reveals Their Bold, Bright Col­ors and Pat­terns

Watch Art on Ancient Greek Vas­es Come to Life with 21st Cen­tu­ry Ani­ma­tion

What Did Ancient Greek Music Sound Like?: Lis­ten to a Recon­struc­tion That’s ‘100% Accu­rate’

An 8‑Minute Ani­mat­ed Flight Over Ancient Rome

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities, the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les and the video series The City in Cin­e­ma. Fol­low him on Twit­ter at @colinmarshall or on Face­book.

The Chrysler Build­ing was once the tallest struc­ture in the world — a hey­day that end­ed up last­ing less than a year. The loss of that glo­ri­ous title owed to the com­ple­tion of the Empire State Build­ing, twelve blocks away, in 1931. But it was all in the spir­it of the game, the Chrysler Build­ing hav­ing itself one-upped its close com­peti­tor 40 Wall Street (then called the Bank of Man­hat­tan Trust Build­ing) by installing a non-func­tion­al spire atop its sig­na­ture crown at the last moment. But how­ev­er much of a tri­umph it rep­re­sent­ed, that moment was poor­ly timed: the very next day would bring the Wall Street Crash of 1929, har­bin­ger of the Great Depres­sion. The sub­se­quent decade would inspire lit­tle pub­lic favor for extrav­a­gant mon­u­ments in the Big Apple.

Yet com­pared to the life of a tow­er, eco­nom­ic cycles are short indeed. By now the Chrysler Build­ing has seen the Unit­ed States of Amer­i­ca through a fair few ups and downs, only gain­ing appre­ci­a­tion all the while. Removed from its imme­di­ate his­tor­i­cal con­text, we can more keen­ly appre­ci­ate archi­tect William Van Alen’s elab­o­rate yet ele­gant Art Deco design.

In the Archi­tec­tur­al Digest video above, archi­tect Michael Wyet­zn­er takes us on a tour of that design, explain­ing how each of its fea­tures works with the oth­ers to make an endur­ing visu­al impact. Some, like the gleam­ing over­sized radi­a­tor-cap gar­goyles, impress with sheer brazen­ness; oth­ers, like the Native Amer­i­can-derived pat­terns that repeat in var­i­ous loca­tions at var­i­ous scales, take a more prac­ticed eye to iden­ti­fy.

Despite hav­ing been sur­passed in height over and over again, the Chrysler Build­ing remains a sine qua non of under­stand­ing the New York sky­scraper. Hence its appear­ance at the very begin­ning of “Why New York’s Sky­scrap­ers Keep Chang­ing Shape” from The B1M. We’ve pre­vi­ous­ly fea­tured that chan­nel here on Open Cul­ture for its inves­ti­ga­tion of why there are so few sky­scrap­ers in Europe; in New York, how­ev­er, the ambi­tious­ly tall build­ing has become some­thing like a force of nature, tamed only tem­porar­i­ly even by cri­sis or dis­as­ter. Some have used the COVID-19 pan­dem­ic to declare an end of the office build­ing, even the end of the city, and much like ear­ly in the Depres­sion, sky­scrap­ers now under con­struc­tion reflect the pri­or­i­ties of a pre­vi­ous real­i­ty. Yet the 92-year-old Chrysler Build­ing con­tin­ues to inspire us today, and to that extent, we still live in the world that made it.

Relat­ed con­tent:

An Intro­duc­tion to the Chrysler Build­ing, New York’s Art Deco Mas­ter­piece, by John Malkovich (1994)

New York’s Lost Sky­scraper: The Rise and Fall of the Singer Tow­er

Watch the Build­ing of the Empire State Build­ing in Col­or: The Cre­ation of the Icon­ic 1930s Sky­scraper From Start to Fin­ish

How the World Trade Cen­ter Was Rebuilt: A Visu­al Explo­ration of a 20-Year Project

A Whirl­wind Archi­tec­tur­al Tour of the New York Pub­lic Library — “Hid­den Details” and All

Famous Archi­tects Dress as Their Famous New York City Build­ings (1931)

Based in Seoul, Col­in Marshall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities, the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les and the video series The City in Cin­e­ma. Fol­low him on Twit­ter at @colinmarshall or on Face­book.