scholarly journals Investigation of Steel Fiber-Reinforced Mortar Overlay for Strengthening Masonry Walls by Prism Tests

2020 ◽  
Vol 10 (18) ◽  
pp. 6395
Author(s):  
Ji-Hoon Yu ◽  
Ji-Hun Park

A strengthening method using steel fiber-reinforced mortar (SFRM), proposed for the seismic retrofit of masonry buildings, is verified experimentally in this study. The SFRM is overlaid on masonry walls directly, which is possible to implement while the building is occupied for residence. First, tests of workability and material strengths were conducted for SFRM itself in order to find SFRM mixing ratios appropriate for overlay construction and strengthening. Then, masonry prisms were produced using two types of bricks and strengthened with SFRM for the chosen mixing ratios and test variables such as the number of overlaid sides and the fiber volume fraction. Compressive strength tests and diagonal tension tests for those specimens were conducted. Both compressive and shear strengths were improved the most highly by overlaying the SFRM with a fiber volume fraction of 1.3%, which is the highest among the test variables, on both sides. Overlaid SFRM tends to be detached without cracking almost at the maximum strength in both compression and diagonal tension tests. For red clay brick prisms, the compressive and shear strengths increased by up to 61% and 138%, respectively. For concrete brick prisms, the compressive and shear strengths increased by up to 26% and 67%. Finally, a design formula for the shear strength of strengthened masonry prisms is compared with the experimental results, and it is observed that the design formula gives slightly higher results.

2012 ◽  
Vol 476-478 ◽  
pp. 1568-1571
Author(s):  
Ting Yi Zhang ◽  
Guang He Zheng ◽  
Ping Wang ◽  
Kai Zhang ◽  
Huai Sen Cai

Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effects of influencing factors including water-cement ratio (W/C) and the fiber volume fraction (ρf) upon the critical value(JC) of J integral were studied. The results show that the variation tendencies of JC are different under different factors. JC meets the linear statistical relation with W/C, ρf, respectively.


2013 ◽  
Vol 539 ◽  
pp. 99-102
Author(s):  
Hai Tao Tan ◽  
Wu Yao ◽  
Xiao Ming Song ◽  
Shuai Dong

The ultimate load, fracture energy and equivalent bending strength of hybrid steel fiber reinforced mortar were investigated with a constant fiber volume fraction in this paper. The results showed that ultimate load of hybrid steel-fiber reinforced mortar was higher than that of mono-fiber reinforced mortar; fracture energy and equivalent bending strength increased with the volume fraction of steel fiber with end hooks.


2010 ◽  
Vol 163-167 ◽  
pp. 3569-3574
Author(s):  
Hong Qiang Cheng ◽  
Dan Ying Gao

Shrinkage experiments were done to determine the influence of the volume fraction of steel fiber-reinforcement on the bonding behavior between new concrete and old concrete. The mechanics of the model of restricted shrinkage upon the adherence of new steel fiber reinforced concrete to old concrete are described. The results demonstrate that the difference of shrinkage between the new and the old concrete can been reduced by adding steel fiber to the new concrete. The decrease of shrinkage difference reduces the shrinkage force at the adhesive interface, which improves the adhesion of new concrete to old concrete and the magnitude of the decrease of shrinkage difference is correlated to the steel fiber volume fraction.


2014 ◽  
Vol 578-579 ◽  
pp. 501-504
Author(s):  
Guo Chao Wang ◽  
Bo Xin Wang

The incorporation of a small amount of steel fibers or fine polypropylene fibers in concrete can increase its impact resistance. But steel fiber has the problems of corrosion, high cost and high mess. The effect of fine polypropylene fibers in inhibiting the impact crack is not effective. The research was taken to measure the properties of fresh concrete mixture of Synthetic Macro-fiber reinforced concrete. And investigated the influence of fiber length and volume fraction on the impact resistance of Synthetic Macro-fiber reinforced concrete. The results showed that these fibers could obviously improve the impact resistance of concrete. There was a best Synthetic Macro-fiber volume fraction. The length of the Synthetic Macro-fiber had a certain influence on the impact resistance of concrete.


2021 ◽  
Vol 11 (13) ◽  
pp. 5974
Author(s):  
Ji-Hoon Yu ◽  
Ji-Hun Park

A technique for strengthening masonry walls by plastering with amorphous steel fiber-reinforced mortar (ASFRM) is investigated through compressive and diagonal tension tests for masonry prisms. The vertical joint between masonry units was not completely filled with mortar to mimic poor workmanship, which is typically reflected in low-cost buildings. The test variables include the number and thickness of mortar overlays, fiber volume fraction, and additional reinforcement using glass fiber mesh or shear connectors. In most strengthened specimens, the ASFRM is not damaged but separated from the masonry prisms after its maximum strength is reached. Additional tests for the bond strength between the ASFRM overlay and masonry surface are conducted to evaluate its contribution to the strengthening effects. Based on experimental observations, equations for predicting the compressive and diagonal tension strengths of masonry prisms strengthened with ASFRM are proposed. The compressive strength can be predicted more accurately by considering the asymmetrical distribution of compressive stress when strengthening is performed on only one side. The diagonal tension strength after strengthening can be predicted by incorporating the contribution of the bond strength between the ASFRM overlay and masonry prism to the initial strength.


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