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Development of an innovative water repellent biocide surface treatment for mortars: assessment of their performance by using modern analytical tools and surface analysis

Objective



The aim of this project is: To develop and investigate an innovative formulation (silicone + biocide) to confer water repellency and to control growth of bacteria, fungi, algae and lichens in mortars and mortar monuments. The combination is based on environmental friendly water compatible formulations, to avoid the problem of using aromatic or chlorinated solvents. The performance of this new surface treatment will be evaluated and compared with those of conventional surface treatments. Special attention will be paid to:

i) the stability (chemical and thermal processes of degradation) of silicones
ii) the study of the interface silicone-biocide/mortar

iii) the effects and transformation processes in silicones and mortars induced by biofilms and testing of the efficacy of the biocide in the formulation.
The last two tasks will be accomplished using the recently introduced techniques of environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM), specially suitable for observing both biofilms and inanimate surfaces, but not yet applied to the study of monument deterioration and protection.

The objectives of this project are summarized as follows:

1. To develop a new combined silicone/biocide surface treatment for mortar monuments, based on water compatible formulations, conversely to most freque commercial silicones and biocides, dissolved in aromatic or chlorinated solvents.

2. To establish the performance and durability of this innovative formulation, both laboratory (accelerated tests) and field exposure (a minimum of 10 years is guaranteed) studies will be carried out and compared with those of other commercially available silicones. A survey on monuments, treated in the last two decades either with silicones or separate applications of silicone/biocide, will be directed to obtain information on the performance of past treatments and the efficiency of biocides in different environments.
3. To know the biocidal properties of the formulation and to ascertain their possible application to solve the problem of biodeterioration of water repellent-treated surfaces.

4. Assessment of the effective distribution of the new formulation on mortar surfaces by using modern surface analyses (environmental scanning electron microscopy, atomic force microscopy, grazing angle Fourier transform infrared spectroscopy), and to investigate the formation of microbial films (biofilms), their effects and transformation processes on the different mortars with and without silicones and biocides.

5. To investigate the chemical stability, hydrolysis, and biodegradation processes of different commercial silicones in the environment, and, specifically, testing of the hypothetical failure of silicone-treated surfaces with clay-containing materials.

6. To develop or modify existing procedures for obtaining simple, fast and reliable analytical methods suitable for characterization of biocides, silicones and their degradation products in monuments.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Address
10,Avenida Reina Mercedes 10
41012 Sevilla
Spain

Participants (6)

Biologia i Medi Ambient S.L.
Spain
Address
58,Calle Clot
08018 Barcelona
CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Spain
Address
C/ Serrano Galvache S/n
28033 Madrid
PHASE di R. Balzarotti & C. Sas
Italy
Address
Via Dello Sprone 6-8/R
50125 Firenze
UNIVERSITA DEGLI STUDI DI MESSINA
Italy
Address
Salita Sperone 31 Villaggio S. Agata
98166 Santagata Messina
University of Portsmouth
United Kingdom
Address
White Swan Road
PO1 2DT Portsmouth
Universität Hamburg
Germany
Address
18,Ohnhorststraße 18
22609 Hamburg