Effect of admixtures on the fresh and hardened properties of modern rendering systems

In this paper, the first part of a doctoral project studying the chemistry and mechanism of modernrendering systems is presented. This study is focused on polymer modified renders, a type of material thatpossesses several superior properties to conventional renders, such as better crack resistance, adhesion to substrateand flexural strength. This improves both the workability and the durability of the material. The main partof the project consists of experimental studies focused on the interaction between composition, hardening process,microstructure and transport properties. These studies concentrate on a small but most relevant selection of renderingsystems with different binders and admixtures. Different studies such as vapour transport, capillary waterabsorption and the drying process give good prerequisite durability of rendering systems. The results of theproject will give a better understanding of rendering systems formulated and their constitutive components

Properties of Modern Rendering Systems based on Mineral Binders

Composite mineral–organic materials and in particular cement-organic materials are increasingly used in today’s construction applications and civil engineering projects. Polymer-modified render is a material that possesses several properties superior to conventional renders, such as better workability, crack resistance, adhesion to substrate and flexural strength. This improves the durability of the material. The importance of understanding the mechanisms behind the materials behaviour is crucial when designing new and advanced products for the industry. In this thesis the influences of different organic admixtures on the early age and hardened properties of mortars, such as water retention, plastic shrinkage and drying shrinkage, are investigated. The mechanisms of the hardening process, from plastic to hardened state, moisture transfer and obtained structure are examined. The results show that the cellulose water retainer not only improves water retention, but also significantly introduce air content in both the cement and the cement-lime binder systems. Styrene-butylacrylate-based copolymer significantly increased the flexural strength as expected, but revealed a high dry shrinkage. The combined effect of the air-entrainer and the cellulose ether reduce the plastic shrinkage of all compositions, but increase the drying shrinkage, due to their high air contents, but also the lower elastic modulus created by the entrained air. Styrene-butylacrylate copolymer and vinyl acetate/ethylene copolymer also contribute to improving water retention, but have a significant effect on moisture transport properties

Effect of admixtures on the fresh and hardened properties of modern rendering systems

In this paper, the first part of a doctoral project studying the chemistry and mechanism of modernrendering systems is presented. This study is focused on polymer modified renders, a type of material thatpossesses several superior properties to conventional renders, such as better crack resistance, adhesion to substrateand flexural strength. This improves both the workability and the durability of the material. The main partof the project consists of experimental studies focused on the interaction between composition, hardening process,microstructure and transport properties. These studies concentrate on a small but most relevant selection of renderingsystems with different binders and admixtures. Different studies such as vapour transport, capillary waterabsorption and the drying process give good prerequisite durability of rendering systems. The results of theproject will give a better understanding of rendering systems formulated and their constitutive components

Missfärgning av byggnaders fasader : En kunskapsöversikt

Discolouration of building facades. A knowledge survey Microorganisms that grow on facades can cause extensive discoloration, which often poses a problem for home owners as it can provide an aesthetically unfavourable impression of the building. Fouling occurs as a result of a complex process that involves several parameters, including biological factors, climatic factors and factors related to the building. This report describes and discusses these factors and their implications for the incidence of fouling, based on scientifically published research. One chapter of the report deals with cleaning and maintenance of facades. Based on the knowledge available in the literature suggestions are given for further research that can contribute to decreased problems with discoloured facades. Finally, the report provides references to a number of scientific articles categorized by keywords in order to make it easier for those who want to read more on the topic

Gröna klimatskal - fuktförhållanden, energianvändning och erfarenheter

I Sverige ser vi ett ökat intresse bland byggherrar och fastighetsägare att bygga och förvalta byggnader som har gröna ytor på tak, och även väggar. Med det ökande intresset ökar behovet av att bygga kunskap kring de gröna klimatskalens inverkan på bl a fukt- och temperaturförhållanden i konstruktioner samt energianvändning för byggnaden. Inom ramen för detta projekt har mätningar, simuleringar utförts där kunskapen byggts vidare bland annat för ventilerade gröna väggar och tak. Även intervjuer har utförs, framförallt vad gäller gröna tak där erfarenheter från genomförda projekt har samlats

Klimatskalets yttre lufttäthet - energieffektivitet och fuktsäkerhet

En slutrapport från ett projektet vars syfte var att lyfta och utvärdera möjligheterna med utvändigt lufttäta klimatskal, både vid nyproduktion och vid ombyggnad där klimatskalet skall uppgraderas

Klimatskalets yttre lufttäthet - energieffektivitet och fuktsäkerhet

En slutrapport från ett projektet vars syfte var att lyfta och utvärdera möjligheterna med utvändigt lufttäta klimatskal, både vid nyproduktion och vid ombyggnad där klimatskalet skall uppgraderas