scholarly journals Confinement of Masonry Columns with Natural Lime-Based Mortar Composite: An Experimental Investigation

2021 ◽  
Vol 13 (24) ◽  
pp. 13742
Author(s):  
Valerio Alecci ◽  
Mario De Stefano ◽  
Stefano Galassi ◽  
Raymundo Magos ◽  
Gianfranco Stipo

The paper presents the results of an experimental campaign on the confinement of masonry square columns with fiber-reinforced lime mortar (FRLM) composites made of a natural lime-based matrix. The experimental results show the effectiveness of such a composite for increasing both strength and ductility performances of strengthened columns. Predictive formulas from the literature and from the Italian guidelines CNR-DT 215/2018 do not perfectly fit the experimental outcomes and do not confirm the strength increase of the confined columns. The reason can be attributed to the very low mechanical properties of the natural matrix used to form such a composite. Therefore, considering that the use of a natural and sustainable matrix fully compatible with the masonry substrate is a fundamental requirement for strengthening masonry columns of buildings belonging to architectural heritage, an additional future effort should be made by researchers involved in this field. In particular, for a reliable prediction of the strength of masonry columns confined with composites made of natural matrices, wider experimental campaigns are necessary to refine available formulas with respect to different substrates and component materials.

2010 ◽  
Vol 168-170 ◽  
pp. 408-411
Author(s):  
Xiao Yong Li

Corrosion is a negative contributor on the structural integrity of rock bolt and leads to degradation of the mechanical properties of steel rock bolt. Exposure to chloride, seawater, salt and saltwater and deicing chemical environments influences rock bolt and weakens it. In order to evaluate the influence of corrosion and the size of the steel on the mechanical properties of rock bolt, an experimental investigation was conducted on rock bolt whose rebar is 8, 12, 16, and 18 mm diameter, and which were artificially corroded for 10, 20, 30, 45, 60, 90, and 120 days. By the simulation corrosion test of loaded and unloaded bolts in Na2SO4 solution, the relation curves of the mechanical performance with the corrosive conditions and the corrosion time are given. The mechanical performance is compared between these two types of bolts. At the same time, the influential trend of the load on the mechanical performance of the corroded bolt is analyzed. The laboratory tests suggest that corrosion duration and rebar size had a significant impact on the strength and ductility degradation of the specimens. after being corroded in Na2SO4 solution, both the ultimate bearing capacity and the maximal tensility of loaded bolt decrease far more than those of unloaded bolt, and the endurance and service life of loaded bolt will also be shortened much more severely. The tensile mechanical properties before and after corrosion indicated progressive variation and drastic drop in their values.


2010 ◽  
Vol 7 (2) ◽  
pp. 57
Author(s):  
Jamaludin Kasim ◽  
Shaikh Abdul Karim Yamani ◽  
Ahmad Firdaus Mat Hedzir ◽  
Ahmad Syafiq Badrul Hisham ◽  
Mohd Arif Fikri Mohamad Adnan

An experimental investigation was performed to evaluate the properties of cement-bonded particleboard made from Sesendok wood. The target board density was set at a standard 1200 kg m". The effect offarticle size, wood to cement ratio and the addition ofsodium silicate and aluminium silicate on the wood cement board properties has been evaluated. A change ofparticle size from 1.0 mm to 2.0 mm has a significant effect on the mechanical properties, however the physical properties deteriorate. Increasing the wood to cement ratio from 1:2.25 to 1:3 decreases the modulus ofrupture (MOR) by 11% and the addition ofsodium silicate improves valuesfurther by about 28% compared to the addition ofaluminum silicate. The modulus ofelasticity (MOE) in general increases with increasing cement content, but is not significantly affected by the addition ofsodium silicate or aluminium silicate, although the addition of their mixture (sodium silicate andaluminium silicate) consistentlyyields greater MOE values. Water absorption and thickness swelling is significantly affected by the inclusion ofadditives and better values are attained using higher wood to cement ratios.


Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2694 ◽  
Author(s):  
Shansuo Zheng ◽  
Lihua Niu ◽  
Pei Pei ◽  
Jinqi Dong

In order to evaluate the deterioration regularity for the mechanical properties of brick masonry due to acid rain corrosion, a series of mechanical property tests for mortars, bricks, shear prisms, and compressive prisms after acid rain corrosion were conducted. The apparent morphology and the compressive strength of the masonry materials (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), the shear behavior of the masonry, and the compression behavior of the masonry were analyzed. The resistance of acid rain corrosion for the cement-lime mortar prisms was the worst, and the incorporation of fly ash into the cement mortar did not improve the acid rain corrosion resistance. The effect of the acid rain corrosion damage on the mechanical properties for the brick was significant. With an increasing number of acid rain corrosion cycles, the compressive strength of the mortar prisms, and the shear and compressive strengths of the brick masonry first increased and then decreased. The peak stress first increased and then decreased whereas the peak strain gradually increased. The slope of the stress-strain curve for the compression prisms gradually decreased. Furthermore, a mathematical degradation model for the compressive strength of the masonry material (cement mortar, cement-lime mortar, cement-fly ash mortar, and brick), as well as the shear strength attenuation model and the compressive strength attenuation model of brick masonry after acid rain corrosion were proposed.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 238
Author(s):  
Sujung Son ◽  
Jongun Moon ◽  
Hyeonseok Kwon ◽  
Peyman Asghari Rad ◽  
Hidemi Kato ◽  
...  

New AlxCo50−xCu50−xMnx (x = 2.5, 10, and 15 atomic %, at%) immiscible medium-entropy alloys (IMMEAs) were designed based on the cobalt-copper binary system. Aluminum, a strong B2 phase former, was added to enhance yield strength and ultimate tensile strength, while manganese was added for additional solid solution strengthening. In this work, the microstructural evolution and mechanical properties of the designed Al-Co-Cu-Mn system are examined. The alloys exhibit phase separation into dual face-centered cubic (FCC) phases due to the miscibility gap of the cobalt-copper binary system with the formation of CoAl-rich B2 phases. The hard B2 phases significantly contribute to the strength of the alloys, whereas the dual FCC phases contribute to elongation mitigating brittle fracture. Consequently, analysis of the Al-Co-Cu-Mn B2-strengthened IMMEAs suggest that the new alloy design methodology results in a good combination of strength and ductility.


Author(s):  
I. Annamalai ◽  
K. Karthik ◽  
Nitheesh Kumar ◽  
S. Muthuselvan ◽  
M. Vignesh ◽  
...  

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