scholarly journals Evaluation of Modulus of Elasticity of Wood Exposed to Accelerated Weathering Test by Measuring Ultrasonic Transmission Time

2014 ◽  
Vol 42 (3) ◽  
pp. 275-281 ◽  
Author(s):  
Chun-Young Park ◽  
Gwang-Chul Kim
Keyword(s):  
Modulus Of Elasticity ◽  
Transmission Time ◽  
Accelerated Weathering ◽  
Accelerated Weathering Test

Effects of accelerated weathering test on the properties of larch wood

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7400-7415
Author(s):  
Liting Cheng ◽  
Yajing Di ◽  
Peng Zhao ◽  
Jian Dai ◽  
Zhiguo Yang ◽  
...  
Keyword(s):  
Modulus Of Elasticity ◽  
Wood Properties ◽  
Sem Analysis ◽  
Accelerated Weathering ◽  
Electron Microscopic ◽  
Larch Wood ◽  
Light Yellow ◽  
Accelerated Weathering Test ◽  
Preset Time ◽  
The Relationship

To investigate the changes of larch wood properties under the influence of long-standing exposure to the environment, the QUV accelerated weathering tester (fluorescent UV and condensation testers) was used to accelerate the weathering of wood within a given preset time, and the changes were studied by analogue simulation. The wood color changed noticeably under different weathering time, and it gradually darkened from light yellow to deep reddish brown. Scanning electron microscopic (SEM) analysis revealed that as the weathering time increased, the cell wall was broken, the pits were cracked, and the tracheids were damaged. The results of the energy spectrum analysis (O/C (oxygen/carbon)) showed an increasing trend in the ratio, indicating that the wood underwent an oxidation reaction induced by light. From the values of the two testing indexes and their change patterns with weathering time, the same trend was observed, with the values of modulus of elasticity (MOE) in static bending being greater than that in dynamic bending Ed (the dynamic modulus of elasticity). However, the variability of MOE was greater than that of Ed. A comparative analysis of the two detection indicators was performed. The relationship between the proposed combined correction Ed and weathering time was: y = 0.0000001017 t2 – 0.0006 t + 9.77.

Surface roughness and color characteristics of wood treated with preservatives after accelerated weathering test

2005 ◽  
Vol 250 (1-4) ◽  
pp. 35-42 ◽  
Author(s):  
Ali Temiz ◽  
Umit C. Yildiz ◽  
Ismail Aydin ◽  
Morten Eikenes ◽  
Gry Alfredsen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Accelerated Weathering ◽  
Color Characteristics ◽  
Accelerated Weathering Test

Ethylene Glycol Accelerated Weathering Test: An Improved, Objective Aggregate Durability Test Method

2017 ◽  
Vol 2655 (1) ◽  
pp. 27-35
Author(s):  
Petrus G. L. van Blerk ◽  
Enrico Fletcher ◽  
Seosamh B. Costello ◽  
Theuns F. P. Henning
Keyword(s):  
Ethylene Glycol ◽  
Clay Minerals ◽  
Road Construction ◽  
Test Methods ◽  
Test Method ◽  
Accelerated Weathering ◽  
Visual Interpretation ◽  
Durability Test ◽  
Spalling Fracture ◽  
Accelerated Weathering Test

Ethylene glycol has been used extensively by the concrete and road construction industries to identify rock durability issues associated with smectite clay minerals. The presence of these clay minerals is synonymous with rock degradation under normal environmental wetting and drying cycles. However, such historical test methods are predominately based on a subjective visual interpretation, describing the observed degradation of individual rock pieces at fixed time intervals during the soaking process. In addition, some test methods include complex equations with multiple weighting factors applied to nominated degradation descriptors (e.g., spalling, fracture, and disintegration) used to calculate a single durability indicator. This paper describes the development and implementation of an alternative, nonsubjective accelerated weathering test that also uses ethylene glycol. The research included metamorphic and volcanic rock types used extensively in New Zealand for road construction. The greatest benefit of the proposed new test method is the ability to eliminate the subjective visual assessment described in historical test methods and adequately quantify results to specify contractual acceptance and rejection criteria. The test method also shows that good repeatability is possible from duplicate test samples. However, rock quality and quarry production consistency will influence the ability of the test method to report the same “percentage change in fines” over a prolonged test period. This phenomenon was particularly evident with problematic and lower quality rock. The test findings are well supported by observed field performance, thus giving confidence in the new method’s usefulness.

scholarly journals Durability and Compatibility of Lime-Based Mortars: the Effect of Aggregates

2018 ◽  
Author(s):  
Ana Rita Santos ◽  
Maria do Rosário Veiga ◽  
Luís Matias ◽  
António Santos Silva ◽  
Jorge de Brito
Keyword(s):  
Accelerated Weathering ◽  
Water Protection ◽  
Good Adhesion ◽  
Environmental Actions ◽  
Lime Mortars ◽  
Accelerated Weathering Test ◽  
Main Factors ◽  
Protection Capability ◽  
High Deformability

In order to fully perform their functions and be durable, mortars for renders and plasters are requested to have a set of characteristics that can vary with the type of exposure to external environmental actions and the type of substrate. Generally, they need moderate strength, high deformability, some water protection capability, good adhesion to the substrate, and compatibility with the pre-existent materials. The presence of water and its movement inside the pore structure of the mortars are among the most significant causes of degradation. Moreover, several authors consider that the main factors for durability and good performance of lime-based mortars are mostly related with the good quality of the binder and the use of adequate aggregates. This paper intends to study the effect of ageing on the properties and durability of air lime mortars, using aggregates of different mineralogy. For this purpose, different mortars compositions are exposed to an accelerated weathering test under defined conditions. The obtained characteristics are discussed and compared with the results obtained with the same mortars tested in laboratory conditions. The effects of the aggregate type on the durability of mortars seem to be linked to their effects on the mortars porous structure.

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