Impacts of natural additives on the properties of earth plasters

Pedergnana, Matthieu Joseph
Traditional earth plasters and renders have a long history of usage adapted to the climate history and culture of the population. They procure aesthetics, protection and comfort in the building they are applied on and they are made of local materials and with local workmanship reducing the environmental footprint of the construction and enhancing the social responsibility of the owner. However, earth plasters need to be upgraded to the standard of the construction industry and they need to fulfil the expectations of the users by becoming a strong and long-lasting material while retaining its ease to use, low environmental impact and comfort procuring properties. Thus, the improvement of plasters should be made with materials which will allow the former properties to be conserved while dealing with the issues of strength improvement, water resistance and cohesion enhancement. This research explores the traditional knowledge on earth plaster and investigates the state-of-art of earth mortar stabilization through the usage of natural and local materials and their adaptation to modern construction standards. Accordingly, a type of soil, known to be used for the production of traditional earth mortar was selected and ten types of sands, eleven types of fibres and thirteen types of biopolymers were chosen amongst the diversity of the material available according to their known or expected beneficial impacts on earth mortars. A reference mortar corresponding to the minimum requirements of the existing standards on earth plaster was produced and after that, the traditionally used sand and fibre were substituted with alternative ones in similar quantities or biopolymers such as molasses, linseed oil or egg white were added in different quantities to the earth mortar. Once fully dried, all specimens were tested for their physical, mechanical, durability, hydric and hygric properties to determine the impact of the changes in the mix on the plaster properties and the possibility to use the selected additives for the production of up-to-standard plasters. Mechanical properties obtained from flexural and compressive tests, water resistance properties obtained from erosion and immersion tests and cohesion properties obtained from abrasion tests were improved by the substitution of sands and fibres with alternative ones but even better results were obtained by the addition of biopolymers such as linseed oil, flour paste, cow dung or casein. Such improvements were obtained without impacting the hygric, properties found from the vapour permeability and vapour sorption tests for flour paste or liquid from the decomposition of hay or casein. In conclusion, it was determined that it is possible to improve the properties of earth plasters and increase their resistance and strength without decreasing their high vapour sorption property. It should be noted that, the results obtained here are only valid for the specific soil chosen with the specific additives tested and more work is necessary to understand the principles behind the improvement of the properties in order to generalize the conclusions of this study for all kinds of earthen materials.


Impacts of salinity and fish-exuded kairomone on the survival and macromolecular profile of Daphnia pulex
Bezirci, Gizem; Akkaş, Sara Banu; Rinke, Karsten; YILDIRIM, FERİHA; Kalaylioglu, Zeynep; Severcan, Feride; Beklioğlu, Meryem (2012-03-01)
Global warming is already causing salinization of freshwater ecosystems located in semi-arid regions, including Turkey. Daphnids, which are important grazers on phytoplankton and a major food source for fish and invertebrates, are sensitive to not only changes in salinity levels, but also presence of predators. In this study, the interactive effect of salinity toxicity (abiotic factor) with predation pressure mimicked by the fish-exuded kairomone (biotic factor) and the effect of salt acclimation on daphnid...
Impact of Urban Street Network on BIPV Generation Capacity of Buildings
Duran, Ayca; Akgül, Çağla; Gürsel Dino, İpek (2022-10-11)
Climate change necessitates a critical reconsideration of the built environment since buildings are among the top fossil fuel consumers. Solar energy generation through building integrated photovoltaic (BIPV) systems is one of the most common onsite energy generation methods. However, many factors regarding urban morphology can negatively affect BIPV generation. Urban block typologies and spatial patterns are commonly studied descriptive metrics of an urban morphology that affect the solar energy potential....
Influences of climate and nutrient enrichment on the multiple trophic levels of Turkish shallow lakes
Beklioğlu, Meryem; Levi, Eti E.; Erdogan, Seyda; Ozen, Arda; Filiz, Nur; Bezirci, Gizem; Cakiroglu, Ayse Idil; Tavsanoglu, U. Nihan; Gökçe, Didem; Demir, Nilsun; Ozulug, Mufit; Duran, Mustafa; Özkan, Korhan; Jeppesen, Erik (2020-04-01)
Climate warming threatens the structure and function of shallow lakes, not least those in the Mediterranean climate. We used a space-for-time substitution approach to assess the response of trophic and community structures as well as the richness and evenness of multiple trophic levels to temperature, hydrological, and nutrient constraints. We selected 41 lakes covering wide climatic, hydrological, and nutrient gradients within a short distance for reducing the effect of biogeographical factors in the weste...
Impact of various sands and fibres on the physical and mechanical properties of earth mortars for plasters and renders
Pedergnana, Matthieu; Elias Özkan, Soofia Tahira (2021-11-01)
Earth plasters and renders tend to crack and crumble due to weathering. Their resilience can be improved by adding sand or fibre to the earth mixture. This paper presents an extensive literature review on earth mortar studies and the results of some experiments to strengthen the earth mortars with different sands and fibres. These experiments showed that regardless of the type of fibre or sand used, the impact on shrinkage was positive but negative on mechanical strength. Although 5% chaff improved flexural...
A Proposed model for understanding the impacts of climate change on tangible cultural heritage
Başkan, Emine Gizem; Elias Özkan, Soofia Tahira; Department of Building Science in Architecture (2016)
The increasing influence of climate change on tangible cultural heritage in the 21st century has been recently recognized as one of the main threats to cultural heritage. Therefore, studies dwelling on the anticipated impacts of changes in the climate parameters are relatively new. This study covers the current debate on the anticipated impacts of climate change on tangible heritage. It presents a forecast on how climate change may affect physical, chemical and biological deterioration mechanisms and which ...
Citation Formats
M. J. Pedergnana, “Impacts of natural additives on the properties of earth plasters,” Ph.D. - Doctoral Program, Middle East Technical University, 2022.