Raindrop Influence on the Soil Surface

Soil erosion through various water processes is a worldwide problem. This research is focused on raindrops’ impact on soil surfaces, which is generally considered the initial stage of the erosion process. Splash erosion monitoring was conducted across three experimental sites: Petzenkirchen, Mistelbach (Austria) and Prague (Czech Republic). At each site, the rainfall characteristics (intensity and kinetic energy) were measured by rain gauges and disdrometers, and the impacts on soils (soil loss, soil surface consolidation, changes in soil surface roughness) were evaluated. Several disturbed soil samples with an area of 78.5 cm2 were placed into splash cups prior to each event. The splash cup collects the soil particles that are splashed out of the sample area when a raindrop hits the soil surface. The collected sediment suspension is processed in the laboratory after each event to determine the lost soil mass. Ground photogrammetry was utilized to determine the surface consolidation of a sample caused by a given rainfall event. Results for more than 500 soil samples were included in this study. Relationships between kinetic energy, rainfall intensity and soil loss and consolidation were evaluated.

Surface Consolidation of Model Stone Samples with Carbonated Hydroxyapatite

Recently, numerous studies have been carried out on various. [...]

SURFACE CONSOLIDATION OF WALL PAINTINGS USING LIME NANO-SUSPENSIONS

Within the field of the conservation of historical and cultural monuments, lime nanosuspensions are still a relatively new and unexplored material. This study examines their effect on the consolidation of architectural surfaces and, consequently, on wall paintings. Previous experiments showed that considerably deteriorated materials may not be adequately strengthened using only lime nano-suspensions. Therefore, the effects of their admixtures and gradual applications with silicic acid esters were examined. For verification, a simulation of a deteriorated lime-based paint layer was created on panels of plaster. The results of the consolidation were subsequently studied using objective (peeling test, water absorption capacity test, measuring colour changes using a mobile spectrophotometer) and subjective methods (comparison of visual changes to a set standard and by testing cohesion using a cotton swab). The microstructure of a consolidated paint layer was studied with a scanning electron microscopy. Tests proved that with either individual lime-alcoholic suspensions or with successive applications and mixtures of silicic acid esters it is feasible to achieve good consolidation results, whilst the alkoxysilane content of the agent indisputably increases the consolidating effect of these materials.

Studies of the Performance of Nanostructured and other Compatible Consolidation Products for Historical Renders

This work is inserted in a wider project aiming at the conservation and durability of historical renders, through compatibles techniques and materials; in particular the restitution of cohesion of historical renders, turned friable by the loss of binder due to physical or chemical actions, is studied. Surface consolidation, directed to restore cohesion and stability, is based on the use of materials with aggregating properties. This operation is reached usually through the application of organic or mineral consolidants, but inorganic consolidants (such as calcium hydroxide or ethyl silicate) are preferred due to better compatibility and durability. Based on the results of previous studies, two mineral compatible products were selected: a commercial suspension of nanoparticles of calcium hydroxide in propanol (Nanorestore); a silicate product, consisting on a limewater dispersion of ethyl silicate. Consolidation products were than applied on different mortars samples previously prepared, in order to assess their efficacy by determining their physical, mechanical and microstructural properties before and after the consolidation treatment. Mechanical and physical analyses were performed, such as compression and flexural strenght and superficial hardness. Microstructural and chemical analyses of the consolidation product and of the consolidated samples are also reported.

Microstructural Characterization of Consolidant Products for Historical Renders: An Innovative Nanostructured Lime Dispersion and a More Traditional Ethyl Silicate Limewater Solution

The conservation and durability of historical renders must be carried out through compatible techniques and materials. An important operation is the restitution of historical renders cohesion, turned friable by the loss of binder, usually due to physical and/or chemical actions. Surface consolidation is based on the use of materials with aggregating properties. This operation is reached usually through the application of organic or mineral consolidants, but inorganic consolidants are becoming preferred due to better compatibility and durability. In this article two mineral compatible consolidation products were studied: a commercial suspension of calcium hydroxide nanoparticles in propanol and a limewater dispersion of ethyl silicate. Microscopy (optical and scanning electron microscopy) and X-ray microanalyses of the consolidation products and of the consolidated mortar specimens were carried out. To assess the mechanical properties and product's efficacy, analyses of the compression, flexural strength, and superficial hardness were performed. Microscopy results show that limewater dispersion of ethyl silicate forms platelike silica gels, which can interfere in product penetration. Otherwise, nanolime particles permit homogeneous distribution and optimum penetration on the treated substrate, improving cementing action and the agglomeration process.

Wear and Corrosion Characteristics of the Layers Type (Mn-P) Formed on Aluminium Alloys

Aluminium alloys are the materials of choice when high-strenght-to-weight rations are required in structural components, and used widely in the automotive and aerospace industries. As an example, the use of an aluminium components in the automobile industry has greatly increased due to weight savings and resultant fuel economy improvements. There are many methods of surface consolidation of an aluminium alloys. This work presents the hybrid creation method of the newly layers type (Mn-P) on the AlSi13Mg1CuNi alloy, its microstructure, hardness, chemical and phase compositions as well as wear and corrosion resistance. Growth the wear resistance of an aluminium alloy coated with the layer type (Mn-P) is visable. The corrosion characteristics of these layers are also considered.