Cemento armato in riva al mare Reinforced concrete at ... - Torggler
Cemento armato in riva al mare Reinforced concrete at ... - Torggler
Cemento armato in riva al mare Reinforced concrete at ... - Torggler
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<strong>Cemento</strong> <strong>arm<strong>at</strong>o</strong><br />
<strong>in</strong> <strong>riva</strong><br />
<strong>al</strong> <strong>mare</strong><br />
PROBLEMATICHE<br />
Marcelli è una cittad<strong>in</strong>a b<strong>al</strong>neare dell’Adri<strong>at</strong>ico, <strong>in</strong> prov<strong>in</strong>cia<br />
di Ancona, car<strong>at</strong>terizz<strong>at</strong>a da una forte vocazione turistica.<br />
Alla diffusa domanda di turismo familiare esplosa negli anni<br />
Settanta, Marcelli, come quasi tutte le loc<strong>al</strong>ità costiere,<br />
risponde con la costruzione “veloce” di edifici per <strong>al</strong>loggi<br />
con struttura a telaio portante <strong>in</strong> cemento <strong>arm<strong>at</strong>o</strong> e<br />
tamponamenti <strong>in</strong> l<strong>at</strong>erizio for<strong>at</strong>o. A questa tipologia<br />
appartiene il Condom<strong>in</strong>io G<strong>al</strong>assia costituito da tre fabbric<strong>at</strong>i<br />
dest<strong>in</strong><strong>at</strong>i ad uso residenzi<strong>al</strong>e ed ubic<strong>at</strong>i <strong>in</strong> prossimità del<br />
<strong>mare</strong>, d<strong>al</strong> qu<strong>al</strong>e è separ<strong>at</strong>o d<strong>al</strong>la strada costiera.<br />
La particolare ubicazione del condom<strong>in</strong>io, cioè la persistente<br />
esposizione dei manuf<strong>at</strong>ti <strong>al</strong>l’azione aggressiva<br />
dell’ambiente mar<strong>in</strong>o, ha contribuito ad <strong>in</strong>nescare il processo<br />
di degrado delle strutture<br />
<strong>in</strong> c<strong>al</strong>cestruzzo <strong>arm<strong>at</strong>o</strong><br />
che, pur senza<br />
compromettere la<br />
funzion<strong>al</strong>ità st<strong>at</strong>ica dei<br />
telai, risultava evidente<br />
per la presenza di<br />
cavill<strong>at</strong>ure e per<br />
l’affioramento dei ferri di<br />
arm<strong>at</strong>ura. Le an<strong>al</strong>isi<br />
prelim<strong>in</strong>ari (prove<br />
colorimetriche <strong>al</strong>la<br />
f e n o l f t a l e i n a )<br />
evidenziavano lo st<strong>at</strong>o di<br />
avanz<strong>at</strong>a carbon<strong>at</strong>azione<br />
del c<strong>al</strong>cestruzzo che aveva<br />
caus<strong>at</strong>o l’ossidazione dei<br />
ferri di arm<strong>at</strong>ura, il<br />
rel<strong>at</strong>ivo aumento di<br />
volume e il conseguente<br />
distacco di ampie porzioni<br />
di copriferro.<br />
PROBLEMS<br />
Re<strong>in</strong>forced<br />
<strong>concrete</strong> <strong>at</strong> the sea<br />
Marcelli is a town on the Adri<strong>at</strong>ic coast <strong>in</strong> the prov<strong>in</strong>ce of<br />
Ancona and is a busy tourist resort. Tourism boomed <strong>in</strong> the<br />
1970s and Marcelli, like <strong>al</strong>most <strong>al</strong>l seaside areas, saw much<br />
new residenti<strong>al</strong> build<strong>in</strong>g. The preferred construction<br />
method was re<strong>in</strong>forced <strong>concrete</strong> frame with hollow brick<br />
curta<strong>in</strong> w<strong>al</strong>ls. The G<strong>al</strong>assia Condom<strong>in</strong>ium consists of three<br />
residenti<strong>al</strong> build<strong>in</strong>gs <strong>al</strong>ongside the coast road and therefore<br />
close to the sea.<br />
The particular loc<strong>at</strong>ion of the condom<strong>in</strong>ium and its<br />
constant exposure to the aggressive action of the sea<br />
environment had caused<br />
considerable damage to<br />
the re<strong>in</strong>forced <strong>concrete</strong><br />
structures. The stability of<br />
the framework was not<br />
compromised but the<br />
<strong>concrete</strong> was cracked and<br />
the re<strong>in</strong>forcement bars<br />
were protrud<strong>in</strong>g.<br />
Prelim<strong>in</strong>ary an<strong>al</strong>ysis<br />
(phenolphth<strong>al</strong>e<strong>in</strong> colour<br />
test<strong>in</strong>g) reve<strong>al</strong>ed<br />
advanced carbon<strong>at</strong>ion of<br />
the <strong>concrete</strong> and<br />
consequent oxid<strong>at</strong>ion of<br />
the re<strong>in</strong>forcement bars.<br />
Tests <strong>al</strong>so showed an<br />
<strong>in</strong>crease <strong>in</strong> volume and<br />
the separ<strong>at</strong>ion of<br />
considerable portions of<br />
the re<strong>in</strong>forcement bar<br />
protections.
LE FASI DELL’INTERVENTO WORKING STEPS<br />
La prima operazione è consistita e nell’asportazione delle<br />
parti f<strong>at</strong>iscenti e disancor<strong>at</strong>e e nella demolizione delle parti di<br />
c<strong>al</strong>cestruzzo fessur<strong>at</strong>o, f<strong>in</strong>o <strong>al</strong> r<strong>in</strong>venimento dei ferri i qu<strong>al</strong>i<br />
sono st<strong>at</strong>i messi a nudo e idrosabbi<strong>at</strong>i “a met<strong>al</strong>lo bianco”.<br />
Conclusa questa prima fase, è st<strong>at</strong>o applic<strong>at</strong>o, <strong>in</strong> due mani,<br />
Antol Riprist<strong>in</strong>o Fondo, un tr<strong>at</strong>tamento che oltre a svolgere<br />
funzione anticorrosiva per i ferri, costituisce anche la<br />
presp<strong>al</strong>m<strong>at</strong>ura di aggrappaggio d<strong>al</strong> momento che consente<br />
un’adesione ottim<strong>al</strong>e della m<strong>al</strong>ta di riprist<strong>in</strong>o. Quando la<br />
seconda mano del fondo era ancora fresca, si è proceduto con<br />
l’applicazione di Antol Riprist<strong>in</strong>o M<strong>al</strong>ta, una m<strong>al</strong>ta<br />
bicomponente tixotropica fibror<strong>in</strong>forz<strong>at</strong>a e res<strong>in</strong><strong>at</strong>a, <strong>in</strong> grado<br />
di contrastare la diffusione dell’anidride carbonica e dot<strong>at</strong>a di<br />
ottime proprietà di ritenzione d’acqua.<br />
Una superficie così estesa come quella <strong>in</strong>teress<strong>at</strong>a<br />
d<strong>al</strong>l’<strong>in</strong>tervento ha richiesto <strong>in</strong> numerosi punti l’utilizzo di<br />
una m<strong>al</strong>ta che oltre ad offrire buona resistenza meccanica,<br />
consentisse un veloce avanzamento dei lavori. Si è utilizz<strong>at</strong>a<br />
a questo scopo Antol Restauro, una m<strong>al</strong>ta pronta <strong>al</strong>l’uso,<br />
rapida, fibror<strong>in</strong>forz<strong>at</strong>a a base di cementi speci<strong>al</strong>i, <strong>in</strong>erti<br />
selezion<strong>at</strong>i, res<strong>in</strong>e s<strong>in</strong>tetiche e additivi speci<strong>al</strong>i <strong>in</strong> grado di<br />
<strong>in</strong>tegrarsi e <strong>in</strong>teragire <strong>in</strong> maniera ottim<strong>al</strong>e con gli str<strong>at</strong>i<br />
sottostanti, aggiungendo il vantaggio della rapidità.<br />
Seguendo le prescrizione di progetto, per la f<strong>in</strong>itura<br />
superfici<strong>al</strong>e è st<strong>at</strong>a applic<strong>at</strong>a Antol Riprist<strong>in</strong>o Rasante, una<br />
m<strong>al</strong>ta f<strong>in</strong>a per ras<strong>at</strong>ura bicomponente, dot<strong>at</strong>a di elev<strong>at</strong>a<br />
resistenza <strong>al</strong>la diffusione dell’anidride carbonica e, agendo<br />
s<strong>in</strong>ergicamente con gli str<strong>at</strong>i sottostanti, <strong>in</strong> grado di garantire<br />
la durabilità del c<strong>al</strong>cestruzzo bonific<strong>at</strong>o sia d<strong>al</strong> punto di vista<br />
st<strong>at</strong>ico sia da quello estetico.<br />
PRODOTTI UTILIZZATI - PRODUCTS USED<br />
• Antol Riprist<strong>in</strong>o Fondo<br />
pag. 41<br />
• Antol Riprist<strong>in</strong>o M<strong>al</strong>ta<br />
pag. 41<br />
• Antol Restauro<br />
pag. 41<br />
• Antol Riprist<strong>in</strong>o Rasante<br />
pag. 41<br />
15<br />
The first oper<strong>at</strong>ion was the remov<strong>al</strong> of the loose and<br />
crumbl<strong>in</strong>g parts and the demolition of the cracked <strong>concrete</strong><br />
parts, until the re<strong>in</strong>forcement bars were exposed. These bars<br />
were then cleaned and w<strong>at</strong>er-sanded blasted down to the<br />
white met<strong>al</strong>. The next stage <strong>in</strong>volved the applic<strong>at</strong>ion, <strong>in</strong> two<br />
co<strong>at</strong>s, of Antol Riprist<strong>in</strong>o Fondo, which, as well as ensur<strong>in</strong>g<br />
corrosion-proof<strong>in</strong>g for the bars, is <strong>al</strong>so a prelim<strong>in</strong>ary gripper<br />
co<strong>at</strong> as it ensures optim<strong>al</strong> adhesion of the repair mortar.<br />
When the second<br />
co<strong>at</strong> was still<br />
fresh, Antol<br />
Riprist<strong>in</strong>o M<strong>al</strong>ta<br />
was applied, a<br />
two-component<br />
thixotropic fibrere<strong>in</strong>forced<br />
and<br />
r e s i n - b o n d e d<br />
mortar, which<br />
protects aga<strong>in</strong>st<br />
the diffusion of<br />
carbon dioxide<br />
and which is<br />
highly w<strong>at</strong>erretentive.<br />
A surface as large<br />
as this required, <strong>in</strong><br />
numerous po<strong>in</strong>ts,<br />
the use of a mortar<br />
which, as well as<br />
offer<strong>in</strong>g high mechanic<strong>al</strong> resistance, permitted fast and<br />
efficient work. For this reason, Antol Restauro was used.<br />
This is a ready-to-use, rapid, fibre-re<strong>in</strong>forced mortar, based<br />
on speci<strong>al</strong> cements, select <strong>in</strong>ert agents, synthetic res<strong>in</strong>s and<br />
speci<strong>al</strong> additives capable of <strong>in</strong>teract<strong>in</strong>g and <strong>in</strong>tegr<strong>at</strong><strong>in</strong>g<br />
perfectly with the layers below. It is <strong>al</strong>so a rapid m<strong>at</strong>eri<strong>al</strong> to<br />
use.<br />
Follow<strong>in</strong>g the procedure chosen, the surface f<strong>in</strong>ish used<br />
Antol Riprist<strong>in</strong>o Rasante, a f<strong>in</strong>e two-component smooth<strong>in</strong>g<br />
mortar, with high resistance to the diffusion of carbon<br />
dioxide and, act<strong>in</strong>g together with the layers below, capable<br />
of guarantee<strong>in</strong>g the durability of the <strong>concrete</strong>, <strong>in</strong> terms of<br />
both stability and aesthetic appe<strong>al</strong>.