scholarly journals Study of the Behavior of Structural Materials Treated with Bioconsolidant

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5369
Author(s):  
Yolanda Spairani ◽  
Arianna Cisternino ◽  
Dora Foti ◽  
Michela Lerna ◽  
Salvador Ivorra

In this article, the effectiveness of the bioconsolidation technique applied to degraded structural materials is illustrated as a new method of consolidation and conservation of the existing building heritage in a less invasive way. Satisfactory results have been obtained by an experimental campaign carried out through non-destructive diagnostic tests, static destructive mechanical tests, and microstructural analyses on a series of natural stone material specimens and artificial stone materials before and after the use of bioconsolidants. The consolidated specimens have been tested after three to four weeks after the application of the M3P nutritional solution on each specimen. The effect on the microstructure of this technique has also been observed using scanning electron microscope and optical photomicrograph, the formation of new calcium carbonate crystals promoting the structural consolidation of the materials under examination was observed in all the specimens analyzed.

Author(s):  
Guillermo Morales-Romero ◽  
Nicéforo Trinidad-Loli ◽  
Adrián Quispe-Andía ◽  
Beatriz Caycho-Salas ◽  
Shirley Quispe-Guía ◽  
...  

<p>The objective of this article is to determine to what extent the automation of the stone materials dosing process, controlled by sequential drive of frequency variators, contributes to improving the productivity of a company dedicated to the production of asphalt in Peru for which, initially, the characteristics of the procedure that will lead to achieving the automation will be described. The results will then be displayed with respect to the indicators used to compare productivity before and after automation. The automation will be done by means of the logo 230RE controller, which will be connected to three frequency inverters, the programming development will be through the logo soft comford V8 software, for the sequential actuation, timers with connection delay will be used. Applying the automation, it is possible to improve the annual efficiency by an average of 58.30%, this is reflected in the monthly decrease in production time by 13.92%, in turn increasing the amount of stone material produced by an average of 43.77%. Likewise, it is possible to significantly reduce the production loss capacity by an annual average of 93.99%.</p>


2020 ◽  
Vol 6 (10) ◽  
pp. 1922-1931
Author(s):  
Anatoly N. Shuvaev ◽  
Anton P. Smirnov ◽  
Sergey V. Kartavy

The paper presents the history of the transport infrastructure of the West-Siberian oil and gas complex in the last century and ways to solve the problems of road construction in the twenty-first century. The development of the territory of Siberia and the North in the present period is constrained by the low rates of development of the transport structure. One of the reasons for this lag is the lack of regulatory documents to substantiate transport structures in the harsh climatic and difficult soil and geological conditions based on the use of new modern road-building materials. The development of new resource-saving materials, structures and technologies based on local building materials, products and industrial waste using modern methods and research methods in materials science is an aim of current study. The general research methodology consisted of theoretical, laboratory and field studies. The developed designs and technologies for the construction of embankments in permafrost and in swamps using geotechnical holders filled with unsuitable soils (thawed and frozen waterlogged peat and clay soils) can reduce the volume of work and the cost of construction by one and a half to two times while increasing the service life of structures. The experimental sites of embankments constructed between 1995 and 2009 in the wetlands of the Uvat Group of deposits in the Tyumen Region and in permafrost in the areas of Novy Urengoy have been observed for more than ten years. The artificial stone material tested in Murmansk and Surgut based on the strengthening of local soils with inorganic binders with polymer additives using modern technologies allows it to be used instead of imported stone materials and reinforced concrete slabs for the construction of structural layers of road pavements, reinforcing slopes, as well as in hydraulic structures. The new artificial stone material is characterized by high strength and durability in areas with a temperature gradient of the external environment of more than 100 (from +50 to -50 °C).


2019 ◽  
Vol 286 ◽  
pp. 95-104
Author(s):  
Natalia Perez-Ema ◽  
Monica Alvarez de Buergo

A silica-based nanoproduct - UCAT-10P© - developed and patented by the TEP-243 (Molecular sieves and other nanomaterials) group of the Cadiz University (UCA) is applied on two stone materials – granite and marble – from the stage front of the Roman theater of Merida, World Heritage by UNESCO (1993). Marble shows firstly scaling as the main decay form, and granite, grain-disintegration, which, at the same time, favor an acceleration of their deterioration condition due to physical, mechanical, chemical and biological processes. That is the reason of assessing the efficiency and durability of a multifuncional nanoproduct, with both consolidating and hydrophobing effects. The performance of this product has been evaluated in terms of the appearance of the stone surfaces (color and roughness), the consolidating role (hardness and ultrasound velocity) and the hydrophobing achievements (capillarity and water contact angle). The most distinctive feature of this research is the in situ testing of the stone blocks, the use of mostly non-destructive and portable techniques, and the monitoring of the product performance of the treatment at a short (1 month) and mid-term (12-15 months), proving the efficacy of the product, although its behavior changes with time.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 567
Author(s):  
Hong Yang ◽  
Mingyu Gao ◽  
Jinxin Wang ◽  
Hongbo Mu ◽  
Dawei Qi

In the absence of high-quality hardwood timber resources, we have gradually turned our attention from natural forests to planted fast-growing forests. However, fast-growing tree timber in general has defects such as low wood density, loose texture, and poor mechanical properties. Therefore, improving the performance of wood through efficient and rapid technological processes and increasing the utilization of inferior wood is a good way to extend the use of wood. Densification of wood increases the strength of low-density wood and extends the range of applications for wood and wood-derived products. In this paper, the effects of ultrasonic and vacuum pretreatment on the properties of high-performance wood were explored by combining sonication, vacuum impregnation, chemical softening, and thermomechanical treatments to densify the wood; then, the changes in the chemical composition, microstructure, and mechanical properties of poplar wood before and after treatment were analyzed comparatively by FT-IR, XRD, SEM, and mechanical tests. The results showed that with ultrasonic pretreatment and vacuum impregnation, the compression ratio of high-performance wood reached its highest level and the MOR and MOE reached their maximums. With the help of this method, fast-growing softwoods can be easily prepared into dense wood materials, and it is hoped that this new material can be applied in the fields of construction, aviation, and automobile manufacturing.


Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 528
Author(s):  
Nikola Perković ◽  
Mislav Stepinac ◽  
Vlatka Rajčić ◽  
Jure Barbalić

The global objective of sustainable development has been greatly directed toward the preservation of existing structures. Therefore, condition assessment and reconstruction of existing timber structures have been gaining importance in recent times. This is particularly evident on timber roofs whose elements are exposed to degradation, either because of rheological effects or due to the direct influence of moisture and biological factors. In case of accidental events, such as an earthquake, the question of the structure’s condition is essential for the condition of the entire building. In order to prove the load-bearing capacity and serviceability of existing structures, as well as to check the need for reconstruction, it is necessary to define crucial parameters that are influencing the condition of materials, elements, and systems. Although there are many non destructive testing methods, the frequency and scope of their use, as well as the decision-making approach, have not been defined. In the paper, non-destructive and semi-destructive methods frequently used for timber structures are explained. A systematic review of criteria to be used in the assessment of load-bearing timber structures in a seismic active area was the main objective of this paper as well as the illustration of non-destructive and semi-destructive test methods through a case study involving roof construction of a hundred-year-old building in Zagreb, Croatia. Pre- and post-earthquake inspection was made. The overall condition of the roof structure after two significant earthquakes can be assessed as satisfactory given that the observed system is a large-span and massive roof structure. The presented results and identification of typical damages after the earthquake are presented in order to facilitate policy makers and for the future implementation of development strategies in the renovation of the city.


2012 ◽  
pp. 189-198 ◽  
Author(s):  
Jelena Petrovic ◽  
Darko Ljubic ◽  
Marina Stamenovic ◽  
Ivana Dimic ◽  
Slavisa Putic

The significance of composite materials and their applications are mainly due to their good properties. This imposes the need for their recycling, thus extending their lifetime. Once used composite material will be disposed as a waste at the end of it service life. After recycling, this kind of waste can be used as raw materials for the production of same material, which raises their applicability. This indicates a great importance of recycling as a method of the renowal of composite materials. This study represents a contribution to the field of mechanical properties of the recycled composite materials. The tension mechanical properties (tensile strength and modulus of elasticity) of once used and disposed glass-epoxy composite material were compared before and after the recycling. The obtained results from mechanical tests confirmed that the applied recycling method was suitable for glass-epoxy composite materials. In respect to the tensile strength and modulus of elasticity it can be further assessed the possibility of use of recycled glass-epoxy composite materials.


Author(s):  
Tomáš Špaček ◽  
Mária Kotlínová ◽  
Michal Kloiber ◽  
Josef Polášek

Non-destructive diagnostic methods are very useful for monumental buildings. This paper deals with one of these technique, namely with ultrasound testing and influence of surface finishing on ultrasound velocity measured by means of device the Arborsonic Decay Detector. Surface finishing (Primalex – thick synthetic film of the surface finishing, Luxol – Extra – thin synthetic film of the surface finishing and Impranal Profi SL – thick acryl film the surface finishing) were selected and tested in this research. The transmittion time was measured and velocity was converted from it. This was compared before and after application of surface finishing.


2020 ◽  
Vol 841 ◽  
pp. 114-118
Author(s):  
Marco Antonio Navarrete Seras ◽  
Francisco Javier Domínguez Mota ◽  
Elia Mercedes Alonso Guzmán ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
...  

. Banks of stone materials from Michoacán, Mexico were characterized, since they are used in the construction of infrastructure in the area. With these materials are made hydraulic concrete mixtures or asphalt mixtures, foundations, paving stones and in restoration of historical monuments. The rocks analyzed and characterized, come from banks of volcanic stone materials and banks of crushed stone materials, which were subjected to mechanical tests such as uniaxial compression resistance (UCR), in addition was used scanning electron microscope (SEM), by means of which the characterization was carried out, obtaining morphological information of the material. The comparison of physical-mechanical properties with the elements they possess is important to estimate their behavior within ceramic matrices or as a structural element.


Author(s):  
Haopeng Wang ◽  
Xueyan Liu ◽  
Panos Apostolidis ◽  
Sandra Erkens ◽  
Athanasios Skarpas

Rubber swelling in bitumen, which is a diffusion-induced volume expansion process, plays a dominant role in the design of crumb rubber modified bitumen binders and their properties development. This study aims to investigate the kinetics of bitumen diffusion into truck tire rubber, the equilibrium swelling characteristics of rubber, and the mechanical properties of rubber before and after swelling at different high temperatures. Fourier transform infrared spectroscopy results indicate that no rubber dissolution happens during the interaction in the temperature range from 160°C to 200°C. Aliphatic compounds from bitumen preferentially diffused into rubber during the swelling process. The diffusion coefficients of bitumen into rubber were determined by the sorption test using the gravimetric method. The diffusion coefficient increases with the increase of temperature in an Arrhenius form. The volume expansion of rubber during swelling was captured by the X-ray computed tomography scan images. Rubber swells faster at the earlier stages, then the expansion rate slows down. The swelling ratio of rubber increased from 1.97 at 160°C to 3.03 at 200°C after 36 h interaction. Mechanical tests by dynamic shear rheometer reveal that swollen rubber becomes softer compared with the dry rubber and exhibits obvious viscoelastic behaviors. With the increase of temperature, the softening and viscous effect are more significant. The obtained parameters can be implemented to swelling and micromechanical models to better predict the binder properties.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1978
Author(s):  
Dan Dobrotă ◽  
Valentin Petrescu ◽  
Cristinel Sabin Dimulescu ◽  
Mihaela Oleksik

An important problem that arises at present refers to the increase in performances in the exploitation of the conveyor belts. Additionally, it is pursued to use some materials, which can be obtained by recycling rubber and PVC waste, in their structure. Thus, the research aimed at creating conveyor belts using materials obtained from the recycling of rubber and PVC waste. Under these conditions, conveyor belts were made that had in their structure two types of rubber and PVC, which was obtained by adding in certain proportions of reclaimed rubber and powder obtained from grinding rubber waste. In order to study the effect of adding PVC on properties, four types of conveyor belts were made, with the structure of rubber, PVC and textile reinforcement. These have been subjected to certain mechanical tests, also being analyzed from the point of view of the behavior of the accelerated aging. The results obtained showed that the addition of PVC lead to a decrease in tensile stress for the strips made, but also an increase in the tensile strain. Additionally, the elasticity tests performed before and after the accelerated aging showed that the presence of PVC in the structure of the conveyor belts determined a substantial reduction of the aging process of the rubber in the conveyor belts. Under these conditions, it has been established that the use of PVC in the structure of rubber matrix conveyor belts is beneficial if conveyor belts are to be produced that are less subject to mechanical stress, but that work in conditions that can cause accelerated aging of materials. An analysis with the finite element method (FEM) of the test samples was also performed.


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