Oro įtraukiančio priedo įtaka tinko, skirto iš autoklavinio akytojo betono blokelių sumūrytoms atitvaroms dengti, savybėms

Abstract

Dėl didelio vandens įgėrio atitvaros, sumūrytos iš autoklavinio akytojo betono (AAC) blokelių, turi būti apsaugotos nuo tiesioginio lietaus poveikio. Tam tikslui naudojami specialūs tinkai, turintys įvairių specifinių priedų, gerinančių tinko savybes. Šiame darbe tirta oro įtraukiančio priedo (OĮP) „Ufapor CC85“ įtaka tinko savybėms - tankiui, stipriui gniuždant, vandens įgerties greičiui, laidumui vandens garams, sukibimui su pagrindu, atsparumui šalčiui bei tinko makrostruktūrai. Nustatyta, kad 0,02 % OĮP priedas suformuoja smulkiaporę struktūrą, užtikrinančią pakankamai gerą vandens garų difuziją (koeficientas m = 9,6). Tinko skiedinys atitinka CS II stiprio gniuždant klasę, pagal kapiliarinę įgertį - W2 klasę, o pagal panaudojimą – lengvojo tinko reikalavimus. Atlikti atsparumo šalčiui tyrimai parodė, kad AAC tinkas atlaikė 35 šaldymo–atšildymo ciklus.

A special type of plaster mortar could be used to protect portions built using autoclave-aerated concrete (AAC) blocks. The plaster to be used for exterior surfaces (taking into account AAC article properties such as porosity, good permeability to water vapour, high water absorption, etc.) should be hydrophobic, possess good adhesion properties to the masonry and be permeable to water vapours. The possibility of water vapour condensation on the plaster and AAC block contact zone arises if the plaster layer permeability differs substantially from that of the AAC article, and thus at outdoor temperatures below zero the protective plaster layer could be destroyed. The aim of our investigation was to determine the affect of the AAA “Ufapor CC85” on industrial AAC plaster properties (macrostructure, density, strength characteristics, water vapour permeability, water absorption rate, adhesion force with the base and frost resistance). The optimal amount of AAA was determined to ensure the conformity of the mentioned properties to LST EN 998-1:2004 “Technical masonry mortar requirements. Part One. Exterior and interior plaster mortars”. It was determined that: – the plaster mortar corresponds to the CS II compressive strength class, according to capillary (0.046 kg/m2 min0.5) water absorption to the w2 class, while according to usage it complies with light plaster requirements – the plaster’s adhesion with porous concrete is very good (>0.2 N/mm2) and its break up line goes through the porous concrete and contact zone; – the use of an air absorbing additive (0.02 based on dry solids) decreases the plaster’s density from 1400 kg/m3 to 1300 kg/m3, while the formed porous structure ensures a good water vapour permeability (water vapour diffusion coefficient   9.6); – the frost resistance investigations showed that AAC plaster endures 35 freezing-thawing cycles.