On site composites-to-masonry bond evaluation in presence of rising damp and salt crystallization

2016 ◽  
pp. 365-372 ◽  
Author(s):  
G. Cardani ◽  
L. Binda ◽  
M.R. Valluzzi ◽  
P. Girardello ◽  
M. Panizza ◽  
...  
Keyword(s):  
Salt Crystallization ◽  
Bond Evaluation ◽  
Rising Damp

Characterization of a Hygro-Regulated Wall Base Ventilation System for Treatment of Rising Damp

2012 ◽  
Vol 326-328 ◽  
pp. 54-59 ◽  
Author(s):  
A.S. Guimarães ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Experimental Research ◽  
Ventilation System ◽  
Experimental Studies ◽  
Salt Crystallization ◽  
Historical Buildings ◽  
New Approach ◽  
Physics Laboratory ◽  
Building Physics ◽  
Rising Damp

The treatment of rising damp in the walls of historical buildings is very complex, due to the thickness and heterogeneity of the walls. The techniques traditionally used for dealing with this problem (such as watertight barriers, injection of hydrofuge products, etc.) have sometimes proved ineffective, and that is why it is necessary to find a new approach. In recent years, the Building Physics Laboratory at the Faculty of Engineering, University of Porto has been conducting experimental research on the effectiveness of the wall base ventilation system, using natural or mechanical higro-regulate systems to reduce the level of the damp area. This experimental research and the simulations that were performed, clearly show that wall base ventilation is a system with potential. This paper presents the characterization of the hygro-regulated systems operation based on experimental studies developed in laboratory, which allowed the influence of the velocity of the air, condensation risk and the possibility of salt crystallization.

The “Humivent” Device for Rising Damp Treatment

2011 ◽  
Vol 5 (3) ◽  
pp. 233-240 ◽  
Author(s):  
V. P. de Freitas ◽  
A. S. Guimaraes ◽  
J. M.P.Q. Delgado
Keyword(s):  
Rising Damp

Salt crystallization pressure as a new method to obtain micro and nanocellulose

Cellulose ◽  
2021 ◽  
Vol 28 (7) ◽  
pp. 4069-4087
Author(s):  
Sandra A. Nascimento ◽  
Eupídio Scopel ◽  
Camila A. Rezende
Keyword(s):  
New Method ◽  
Salt Crystallization ◽  
Crystallization Pressure

Some observations on rock weathering, Cumberland Peninsula, Baffin Island

1979 ◽  
Vol 16 (5) ◽  
pp. 977-983 ◽  
Author(s):  
Stephen H. Waits
Keyword(s):  
Salt Crystallization ◽  
Rock Weathering ◽  
Baffin Island ◽  
Significant Modification ◽  
Bedrock Weathering ◽  
Arctic Conditions ◽  
Selective Preservation ◽  
Mechanical Weathering ◽  
High Level

A variety of bedrock weathering features—both modern and remnant—including surface grus, polygonal cracks, siliceous glaze, tors, weathering pits, and tafoni typify upland outcrops on the Cumberland Peninsula. Tor ridges are particularly prevalent and at lower elevations they show significant modification and streamlining by flowing ice. On summit areas at elevations above 750 m, however, remnant corestones are preserved in situ, suggesting selective preservation of upland surfaces. Bedrock structure and composition, topographic position, and intensity of process strongly influence tor development. Weathering pits are common on high level, open summit surfaces where weathering occurs in response to both climate and continued removal of derived debris. Pit enlargement through lateral undercutting has been favoured by accumulation of protective bottom residua, mechanical weathering, and the presence of exfoliation crusts. It is postulated that salt crystallization plays a role in outcrop microweathering under present upland arctic conditions.

Cased borehole acoustic-wave propagation with varying bonding conditions: Theoretical and experimental modeling

Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. D161-D169
Author(s):  
Can Jiang ◽  
Xue-Lian Chen ◽  
Yuan-Da Su ◽  
Xiao-Ming Tang
Keyword(s):  
Acoustic Wave ◽  
Wave Theory ◽  
Acoustic Measurements ◽  
Acoustic Wave Propagation ◽  
Velocity Change ◽  
Slip Boundary ◽  
Wave Measurements ◽  
Bonding Condition ◽  
Bond Evaluation ◽  
Cased Borehole

Acoustic measurements in cased boreholes are important for cement-bond evaluation behind the casing. In conjunction with a recently developed acoustic-wave theory using slip-boundary modeling, we carried out an experimental study for different cement-bond conditions. Four different cased-hole models were constructed, where the interface between the casing and the cement, and that between the cement and the formation, are decoupled or partially bonded to simulate the different cement bond conditions. An acoustic system is placed in the borehole to measure extensional casing waves along the borehole. By extracting the attenuation and velocity of casing waves from the experimental data, the bonding conditions were analyzed and compared with the theoretical modeling. The results indicate that, compared with the free-pipe situation, the casing waves are attenuated when there is some degree of bonding (good or poor) between the casing and the formation. However, when the poor bonding occurs at the cement-formation interface, the casing wave indicates significant velocity reduction and dispersion, the degree of the velocity change varying with the bonding condition. This wave phenomenon is predicted by the slip-boundary modeling. By adjusting the slip-boundary parameters in the modeling, the experimental results can be quantitatively modeled. These results are also confirmed by cased-hole acoustic logging data examples. The theoretical model can therefore be used to interpret cased-borehole acoustic-wave measurements.

New sustainable mortars for stone restoration in the context of climate change

2021 ◽  
Author(s):  
Jose Diaz-Basteris
Keyword(s):  
Physical Properties ◽  
Moisture Absorption ◽  
Raw Materials ◽  
Point Of View ◽  
Salt Crystallization ◽  
Glass Waste ◽  
Vapour Permeability ◽  
James Bond ◽  
S Waves ◽  
Environmental Agents

<p>Restoration mortars are a designated group of products made to repair damaged masonry. They must be compatible with the former support of stones and bricks, and protect original materials from environmental agents; aesthetical and historic aspects must not be neglected. </p><p>To improve the ecological footprint of the restoration mortars while keeping their efficiency, we have tested several combinations of lime with aggregates and additives. Recycled and natural materials were used as additives such as pinecone resin, semi-milled cones of pine, milled glass waste, brick production residue.</p><p>For research purposes different physical properties have been measured in prepared mortars: porosity, density, capillarity absorption, moisture absorption, water vapour permeability. We have also tested the mechanical properties and the P and S waves velocities (from which dynamic Young's modulus and Poisson’s ratio were inferred). The durability of mortars has been estimated by salt crystallization and frost/thaw cycles.</p><p>The life cycle analysis (LCA) of such mortars allows us to understand the carbon footprint of each manufacturing process. Considering this we selected the raw materials, from an environmental and commercial point of view, to produce mortars fulfilling sustainability requirements. As a result, the developed mortars are compatible with aged stones, minimize environmental impact, and use minimum natural resources.</p><p> Twenty mortar formulations with three different types of limes (NHL5, NHL3.5, CL90) and two different aggregates (siliceous and calcareous) have been studied using the LCA. Currently, five new formulations are being selected to be tested on Euville limestone. Adhesive strength (James Bond test), and physical properties will be measured on these mortars. </p>

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