Antik Roma, kal\u0131nt\u0131lar\u0131 iki bin y\u0131ld\u0131r ayakta kalan geni\u015f yol a\u011flar\u0131, su kemerleri, limanlar ve devasa binalar in\u015fa ederek m\u00fchendislik alan\u0131nda ne derece usta oldu\u011funu tarihe alt\u0131n harflerle yazd\u0131rd\u0131.\u00a0 Bu yap\u0131lar\u0131n bir\u00e7o\u011fu betonla in\u015fa edildi, \u00f6yle ki Roma’n\u0131n d\u00fcnyan\u0131n en b\u00fcy\u00fck betonarme kubbesine sahip olan ve MS 128’de in\u015fa edilmi\u015f \u00fcnl\u00fc Pantheon hala sa\u011flam ve baz\u0131 antik Roma su kemerleri bug\u00fcn hala Roma’ya su ta\u015f\u0131yor. Bu arada, bir\u00e7ok modern beton yap\u0131 birka\u00e7 on y\u0131l sonra ufalan\u0131p gitti.
\nAra\u015ft\u0131rmac\u0131lar, \u00f6zellikle r\u0131ht\u0131mlar, kanalizasyonlar ve deniz duvarlar\u0131 gibi \u00f6zellikle zorlu ko\u015fullara dayanan yap\u0131larda veya sismik olarak aktif konumlarda in\u015fa edilen yap\u0131larda kullan\u0131lan ultra dayan\u0131kl\u0131 eski yap\u0131 malzemesinin s\u0131rr\u0131n\u0131 \u00e7\u00f6zmek i\u00e7in onlarca y\u0131l harcad\u0131lar.<\/p>\n
Kendini iyile\u015ftirme i\u015flevi<\/strong> \u00c7atlad\u0131k\u00e7a giren “kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131”<\/strong> Antik Roma, kal\u0131nt\u0131lar\u0131 iki bin y\u0131ld\u0131r ayakta kalan geni\u015f yol a\u011flar\u0131, su kemerleri, limanlar ve devasa binalar in\u015fa ederek m\u00fchendislik alan\u0131nda ne derece usta oldu\u011funu tarihe alt\u0131n harflerle yazd\u0131rd\u0131.\u00a0 Bu yap\u0131lar\u0131n bir\u00e7o\u011fu betonla in\u015fa edildi, \u00f6yle ki Roma’n\u0131n d\u00fcnyan\u0131n en b\u00fcy\u00fck betonarme kubbesine sahip olan ve MS 128’de in\u015fa edilmi\u015f \u00fcnl\u00fc Pantheon hala sa\u011flam ve […]<\/p>\n","protected":false},"author":512,"featured_media":57492,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[20,19],"tags":[3480,8835],"class_list":["post-57484","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-arkeoloji","category-bilim-gundemi","tag-antik-roma","tag-beton"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t
\n\u015eimdi ABD’de bulunan Massachussets Teknoloji Enstit\u00fcs\u00fc (MIT), Harvard \u00dcniversitesi ve \u0130talya ile \u0130svi\u00e7re’deki laboratuvarlardan bir grup ara\u015ft\u0131rmac\u0131, bu t\u00fcr betonlardaki “kendi kendini iyile\u015ftirme\/tamir etme” olarak adland\u0131r\u0131labilecek bir y\u00f6nteme ba\u015fvuruldu\u011funu \u00f6\u011frendi. Bulgular Science Advances dergisinde, MIT in\u015faat ve \u00e7evre m\u00fchendisli\u011fi profes\u00f6r\u00fc Admir Masic, eski doktora \u00f6\u011frencisi Linda Seymour ve di\u011fer d\u00f6rt ki\u015finin bir makalesinde yay\u0131nland\u0131.
\nUzun y\u0131llar boyunca ara\u015ft\u0131rmac\u0131lar, antik betonun dayan\u0131kl\u0131l\u0131\u011f\u0131n\u0131n anahtar\u0131n\u0131n tek bir bile\u015fene dayand\u0131\u011f\u0131n\u0131 varsayd\u0131lar: Napoli K\u00f6rfezi’ndeki Pozzuoli b\u00f6lgesinden gelen volkanik k\u00fcl gibi puzolan ad\u0131 verilen malzeme. Bu \u00f6zel k\u00fcl t\u00fcr\u00fc, in\u015faatta kullan\u0131lmak \u00fczere geni\u015f Roma imparatorlu\u011funun her yerine sevk edildi ve o d\u00f6nemde mimarlar ve tarih\u00e7iler taraf\u0131ndan yap\u0131lan hesaplarda beton i\u00e7in \u00f6nemli bir bile\u015fen olarak tan\u0131mland\u0131.
\nBu gizemli beton daha yak\u0131ndan incelendi\u011finde, uzun s\u00fcredir Roma betonunun temel bile\u015fenlerinden biri oldu\u011fu kabul edilen “kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131 (\u0130ng. lime casts)” olarak adland\u0131r\u0131labilecek
\nDaha yak\u0131ndan incelendi\u011finde, bu eski \u00f6rnekler ayr\u0131ca, uzun s\u00fcredir Roma betonlar\u0131da temel bir bile\u015feni olarak kabul edilen milimetre \u00f6l\u00e7e\u011fine kadar k\u00fc\u00e7\u00fck parlak beyaz mineraller bulunur. Genellikle “kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131” olarak adland\u0131r\u0131lan bu beyaz par\u00e7alar, antik \u00e7a\u011flarda \u00fcretilmi\u015f beton \u00fcretimine dair tarif metinlerinde bulunmamakta. O halde beton bulgular\u0131nda neden bulunuyor?
\nDaha \u00f6nce sadece \u00f6zensiz kar\u0131\u015ft\u0131rma uygulamalar\u0131n\u0131n veya d\u00fc\u015f\u00fck kaliteli ham maddelerin kan\u0131t\u0131 olarak g\u00f6z ard\u0131 edilen bu bulgu, k\u00fc\u00e7\u00fck kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131n\u0131n betona daha \u00f6nce fark edilmeyen bir kendi kendini iyile\u015ftirme yetene\u011fi kazand\u0131rd\u0131\u011f\u0131n\u0131 \u00f6ne s\u00fcr\u00fcyor. Zira Romal\u0131lar, y\u00fczy\u0131llar boyunca optimize edilmi\u015f t\u00fcm ayr\u0131nt\u0131l\u0131 tarifleri takip ederek ola\u011fan\u00fcst\u00fc bir yap\u0131 malzemesi yapmak i\u00e7in bu kadar \u00e7ok \u00e7aba harcad\u0131ysa, iyi kar\u0131\u015ft\u0131r\u0131lm\u0131\u015f bir nihai \u00fcr\u00fcn\u00fcn \u00fcretimini sa\u011flamak i\u00e7in neden bu kadar az \u00e7aba sarf etsinler? Bu hikayede daha fazlas\u0131 olmal\u0131.
\nAra\u015ft\u0131rmac\u0131lar, y\u00fcksek \u00e7\u00f6z\u00fcn\u00fcrl\u00fckl\u00fc \u00e7ok \u00f6l\u00e7ekli g\u00f6r\u00fcnt\u00fcleme ve kimyasal haritalama teknikleri kullan\u0131larak bu kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131n\u0131n \u00f6zelliklerinin belirlenmesi \u00fczerine \u00fczerine, bu kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131n\u0131n potansiyel i\u015flevselli\u011fi hakk\u0131nda yeni g\u00f6r\u00fc\u015fler elde ettiler.
\nTarihsel olarak, kirecin Roma betonuna dahil edildi\u011finde, s\u00f6nd\u00fcrme olarak bilinen bir s\u00fcre\u00e7 sonucu, y\u00fcksek oranda etkile\u015fime yatk\u0131n macun benzeri bir malzeme olu\u015fturmak i\u00e7in su ile birle\u015ftirildi\u011fi varsay\u0131lm\u0131\u015ft\u0131r. Ancak bu i\u015flem tek ba\u015f\u0131na kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131n\u0131n varl\u0131\u011f\u0131n\u0131 a\u00e7\u0131klayamaz.<\/p>\n
\nEski beton \u00f6rneklerini inceleyen ekip, beyaz kal\u0131nt\u0131lar\u0131n ger\u00e7ekten de \u00e7e\u015fitli Kalsiyum Karbonat formlar\u0131ndan olu\u015ftu\u011funu belirlediler. Renkserim incelemesi, kar\u0131\u015f\u0131mdaki s\u00f6nm\u00fc\u015f kirecin yerine veya ek olarak s\u00f6nmemi\u015f kire\u00e7 kullan\u0131larak, betonun y\u00fcksek s\u0131cakl\u0131klarda meydana geldi\u011fine dair ipu\u00e7lar\u0131 elde ettiler. Ekip, y\u00fcksek s\u0131cakl\u0131klarda yap\u0131lan beton kar\u0131\u015ft\u0131rma i\u015fleminin, betonun s\u00fcper dayan\u0131kl\u0131 do\u011fas\u0131n\u0131n anahtar\u0131 oldu\u011fu sonucuna vard\u0131.
\nBetonu s\u0131cak kar\u0131\u015ft\u0131rman\u0131n iki faydal\u0131 yan\u0131 bulunmakta. \u0130lk olarak, genel beton y\u00fcksek s\u0131cakl\u0131klara \u0131s\u0131t\u0131ld\u0131\u011f\u0131nda, yaln\u0131zca s\u00f6nm\u00fc\u015f kire\u00e7 kulland\u0131\u011f\u0131n\u0131zda olu\u015fmas\u0131 m\u00fcmk\u00fcn olmayan kimyasallar\u0131 olu\u015fturarak, ba\u015fka t\u00fcrl\u00fc olu\u015fmayacak olan y\u00fcksek s\u0131cakl\u0131kla ili\u015fkili bile\u015fikler \u00fcretir. \u0130kincisi, bu artan s\u0131cakl\u0131k, sertle\u015fme s\u00fcresini \u00f6nemli \u00f6l\u00e7\u00fcde azalt\u0131r, \u00e7\u00fcnk\u00fc t\u00fcm tepkimeler h\u0131zlan\u0131r ve in\u015faat\u0131n da h\u0131zlanmas\u0131 sa\u011flan\u0131r.
\nS\u0131cak kar\u0131\u015ft\u0131rma i\u015flemi s\u0131ras\u0131nda, kire\u00e7 k\u0131r\u0131nt\u0131lar\u0131 karakteristik olarak k\u0131r\u0131lgan bir nanopar\u00e7ac\u0131k mimaris\u0131 geli\u015ftirerek, ekibin \u00f6nerdi\u011fi gibi, kritik bir kendi kendini iyile\u015ftirme i\u015flevi sa\u011flayabilecek ve kolayca k\u0131r\u0131labilen bir kalsiyum kayna\u011f\u0131 olu\u015fturur. Betonda k\u00fc\u00e7\u00fck \u00e7atlaklar olu\u015fmaya ba\u015flar ba\u015flamaz, y\u00fcksek y\u00fczey alanl\u0131 kire\u00e7 kal\u0131nt\u0131lar\u0131 i\u00e7eri girmeye ba\u015flar. Akabinde\u00a0 suyla tepkimeye girerek kalsiyum karbonat olarak yeniden kristalle\u015febilen ve \u00e7atla\u011f\u0131 h\u0131zla doldurabilen kalsiyuma doymu\u015f bir \u00e7\u00f6zelti olu\u015fur ve beton “iyile\u015fmi\u015f” olur.
\nBunun ger\u00e7ekten de Roma betonunun dayan\u0131kl\u0131l\u0131\u011f\u0131ndan sorumlu mekanizma oldu\u011funu kan\u0131tlamak i\u00e7in ekip, hem eski hem de modern beton yapma tarifleri arac\u0131l\u0131\u011f\u0131yla s\u0131cak kar\u0131\u015f\u0131m beton numuneleri \u00fcretti, bunlar\u0131 kas\u0131tl\u0131 olarak k\u0131rd\u0131 ve ard\u0131ndan \u00e7atlaklardan su ak\u0131tt\u0131. \u0130ki hafta i\u00e7inde antik Roma betonu oldu\u011fu d\u00fc\u015f\u00fcn\u00fclen \u00f6rnekte \u00e7atlaklar tamamen iyile\u015fti ve su art\u0131k akamaz hale geldi. S\u00f6nmemi\u015f kire\u00e7 kullan\u0131lmadan yap\u0131lm\u0131\u015f \u00f6zde\u015f bir beton par\u00e7as\u0131 asla iyile\u015fmedi ve su, numunenin i\u00e7inden akmaya devam etti. Bu ba\u015far\u0131l\u0131 testler sonucunda ekip, bu modifiye edilmi\u015f \u00e7imento malzemesini ticarile\u015ftirmek i\u00e7in \u00e7al\u0131\u015f\u0131yor.
\nUzat\u0131lm\u0131\u015f i\u015flevsel \u00f6m\u00fcr ve daha hafif beton formlar\u0131n geli\u015ftirilmesi sayesinde, bu \u00e7abalar\u0131n \u015fu anda k\u00fcresel sera gaz\u0131 yay\u0131l\u0131mlar\u0131n\u0131n yakla\u015f\u0131k y\u00fczde 8’ini olu\u015fturan \u00e7imento \u00fcretiminin \u00e7evresel etkisini azaltmaya yard\u0131mc\u0131 olabilece\u011fini umuyor. Ayr\u0131ca ekip, bir ba\u015fka g\u00fcncel ara\u015ft\u0131rma oda\u011f\u0131 olan havadaki karbondioksiti ger\u00e7ekten emebilen beton gibi di\u011fer yeni fikirler de \u00fcretmekte olduklar\u0131n\u0131 s\u00f6yl\u00fcyorlar.<\/p>\n