Identification of moisture content in brick walls by means of impedance tomography

Abstract

Purpose -This paper aims to present a new non-destructive method of brick wall dampness testing in real building structures. The electrical impedance tomography (EIT) method makes it possible to obtain a distribution of wall dampness. The paper aims to give basic information about the measuring system, including prototype equipment. The setup was used to determine the dampness of test brick walls on a specially built laboratory test rig. The paper seeks to compare test results obtained by the non-destructive impedance tomography method with the results obtained by the conventional destructive dry-weight method. Design/methodology/approach -The paper adopts a tomography approach to control humidity inside of the brick walls. In case of brick walls other nondestructive methods fields, for example, the ultrasonic tomography is useless. On the other hand the most popular dry-weight method is strictly forbidden for historical buildings. As a forward solver, functionally graded material boundary element method was used. Findings -The paper proves that diffuse tomography could provide reliable results with respect of humidity content inside the brick walls. This method could provide 3D humidity distribution inside of the brick walls. Research limitations/implications -It is expected that the technique's impact will be limited to site inspection of building following floods or to evaluate older damp buildings. Practical implications -The presented technique can eventually lead to much simpler, cheaper and more efficient evaluation of the moisture content in walls. This can revolutionize some procedures in civil engineering. Social implications -The application has commercial potential and could result in more cost-effective repair of old buildings, which has an economic impact on society. Originality/value -The authors propose application of the diffuse tomography for nondestructive investigation of brick walls. According to the authors' best knowledge this is a novel approach.

The Experimental Research on Special Polymerized Sulfur Composite- Impregnated Concrete and Cement Mortar

“…Generally speaking, the fight against corrosion comes down to providing a given material or element with protection whereby its failure free service life is significantly extended [16][17][18][19][20][21].…”

City sewer collectors biocorrosion

“…The obvious aim was always "better concrete" [1][2][3][4][15][16][17]. The general material concept of polymer concretes covers -from the technological point of view -the process during which the monomers, oligomers, pre-polymers or polymers are introduced into the concretes mix and, if chemically active, undergo to polymerization or polycondensation, usually initiated by catalysts [2][3][4][5][6][7][8][24][25][26][27][28].…”

New electrical tomographic method to determine dampness in historical buildings

“…Before performing such tasks or even their planning, it is necessary to conduct spe-cialized research on the level of dampness and its distribution in walls, both in thickness and height. The results of these measurements have substantial influence on the choice of the adequate protection against the moisture and procedure against the excessive salinity [1]. They should also be a reference point for analogous control measurements conducted later to assess protection quality and speed of walls desiccation.…”

“…The vast majority of European buildings made of ceramic bricks before 1945 and almost 100% of such constructions raised till 1920 have insufficient damp-proof insulation or do not possess it at all [1]. It mostly concerns horizontal damp-proof protection.…”

“…Water accumulated in walls creates the adverse microclimate in rooms, deteriorates thermal insulation and acoustic properties of barriers and contributes to gradual wall destruction, loosening of the plaster and paint coatings. A high moisture content inside walls along with high humidity in rooms, partially due to the lack of the proper ventilation, ease the development of the true fungi and mould which both negatively affect human health [1]. The electrical impedance tomography (EIT) is a technique of imaging distribution of conductivity inside the tested object based on measurements of the distribution of potentials on the object's surface [7].…”