scholarly journals State-of-the-Art Report on Fiber-Reinforced Lightweight Aggregate Concrete Masonry

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Saul Rico ◽  
Roshanak Farshidpour ◽  
Fariborz M. Tehrani
Keyword(s):  
Lightweight Aggregate ◽  
Fiber Reinforced Concrete ◽  
Lightweight Aggregate Concrete ◽  
Seismic Loads ◽  
Fiber Reinforced ◽  
Masonry Unit ◽  
Aggregate Concrete ◽  
Masonry Construction ◽  
Concrete Masonry

Masonry construction is the most widely used building method in the world. Concrete masonry is relatively low in cost due to the vast availability of aggregates used within the production process. These aggregate materials are not always reliable for structural use. One of the principal issues associated with masonry is the brittleness of the unit. When subject to seismic loads, the brittleness of the masonry magnifies. In regions with high seismic activity and unspecified building codes or standards, masonry housing has developed into a death trap for countless individuals. A common approach concerning the issue associated with the brittle characteristic of masonry is addition of steel reinforcement. However, this can be expensive, highly dependent on skillfulness of labor, and particularly dependent on the quality of available steel. A proposed solution presented in this investigation consists of introducing steel fibers to the lightweight aggregate concrete masonry mix. Previous investigations in the field of lightweight aggregate fiber-reinforced concrete have shown an increase in flexural strength, toughness, and ductility. The outcome of this research project provides invaluable data for the production of a ductile masonry unit capable of withstanding seismic loads for prolonged periods.

scholarly journals An Experimental Investigation of Dynamic Properties of Fiber-Reinforced Tire-Derived Lightweight-Aggregate Concrete

2020 ◽  
Vol 5 (6) ◽  
pp. 702-707
Author(s):  
Fariborz M. Tehrani ◽  
Nazmieh A. Masswadi ◽  
Nathan M. Miller ◽  
Arezoo Sadrinezhad
Keyword(s):  
Energy Absorption ◽  
Dynamic Properties ◽  
Fiber Reinforcement ◽  
Lightweight Aggregate ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Aggregate Concrete

This paper presents the results of an experimental study to investigate dynamic properties of polypropylene fiber-reinforced concrete beams with lightweight expanded shale (ES) and tire-derived aggregates (TDA). The mixture design followed past experiences in combining ES and TDA to enhance toughness and energy absorption in flexural behavior. The new mixture also contained 2% fiber by volume to improve such properties further. Experiments included compressive testing on cylindrical specimens as well as flexural testing on rectangular specimens to verify mechanical properties of fiber-reinforced tire-derived lightweight aggregate concrete (FRTDLWAC) subject to static loading. The results of these experiments confirmed reduction of mechanical strength due to addition of TDA and improvements in flexural strength due to fiber reinforcement. The dynamic testing included non-destructive impact loads applied to flexural specimens using a standard Schmidt hammer. A high-speed camera recorded the response of the system at 200 frames per second to allow detailed observations and measurements. Interpretation of energy-based dynamic results revealed that TDA enhances energy absorption through damping in flexural behavior. Results also indicated that fiber reinforcement reduces the amount of absorbed dynamic energy, even though; it enhances the absorbed strain energy due to crack bridging effect.

scholarly journals Flexural Capacity and Deflection of Fiber-Reinforced Lightweight Aggregate Concrete Beams Reinforced with GFRP Bars

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 873 ◽  
Author(s):  
Xi Liu ◽  
Yijia Sun ◽  
Tao Wu
Keyword(s):  
Lightweight Aggregate ◽  
Reinforcement Ratio ◽  
Steel Fibers ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Flexural Capacity ◽  
Short Term ◽  
Aggregate Concrete ◽  
Reinforced Polymer ◽  
Stiffness Model

Adding fibers is highly effective to enhance the deflection and ductility of fiber-reinforced polymer (FRP)-reinforced beams. In this study, the stress and strain conditions of FRP-reinforced lightweight aggregate concrete (LWC) beams with and without fibers at ultimate load level were specified. Based on the sectional analyses, alternative equations to predict the balanced reinforcement ratio and flexural capacity for beams failed by balanced failure and concrete crushing were established. A rational equation for estimating the short-term stiffness of FRP–LWC beams at service-load levels was suggested based on Zhu’s model. In addition, the contribution of the steel fibers on the short-term stiffness was quantified incorporating the effects of FRP reinforcement ratio. The proposed short-term stiffness model was validated with measured deflections from an experimental database for fiber-reinforced normal weight concrete (FNWC) beams reinforced with FRP bars. Furthermore, six glass fiber-reinforced polymer (GFRP)-reinforced LWC beams with and without steel fibers were tested under four-point bending. Based on the test results, the proposed models and procedures according to current design codes ACI 440.1R, ISIS-M03, GB 50608, and CSA S806 were linked together by comparing their predictions. The results showed that increasing the reinforcement ratio and adding steel fibers decreased the strain of the FRP bars. The flexural capacity of the LWC beams with and without steel fibers was generally underestimated by the design codes, while the proposed model provided accurate ultimate moment predictions. Moreover, the proposed short-term stiffness model yielded reasonable estimations of deflection for both steel fiber-reinforced lightweight aggregate concrete (SFLWC) and FNWC beams.

scholarly journals Properties of Lightweight Aggregate Concrete Reinforced with Carbon and/or Polypropylene Fibers

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 640 ◽  
Author(s):  
Hui Wei ◽  
Tao Wu ◽  
Xue Yang
Keyword(s):  
Tensile Strength ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Polypropylene Fibers ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Stress Strain ◽  
Aggregate Concrete ◽  
Ductility Index ◽  
Hybrid Forms

The impact of carbon and polypropylene fibers in both single and hybrid forms on the properties of lightweight aggregate concrete (LWAC), including the slump, density, segregation resistance, compressive strength, splitting tensile strength, flexural strength, and compressive stress–strain behavior, were experimentally investigated. The toughness ratio and ductility index were introduced for quantitatively evaluating the energy-absorbing capacity and post-peak ductility. A positive synergistic effect of hybrid carbon and polypropylene fibers was obtained in terms of higher tensile strength, toughness, and ductility. The toughness ratio and ductility index of hybrid fiber-reinforced LWAC were increased by 26%–37% and 12%–27% compared with plain LWAC, respectively. The fiber in both single and hybrid forms had a smaller effect on the linearity ascending branch of the stress–strain curves, whereas the post-peak patterns in terms of the toughness and ductility for the hybrid fiber-reinforced LWAC were significantly improved when the fiber in hybrid form.

scholarly journals Experimental Study on Autogenous and Drying Shrinkage of Steel Fiber Reinforced Lightweight-Aggregate Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Shunbo Zhao ◽  
Changyong Li ◽  
Mingshuang Zhao ◽  
Xiaoyan Zhang
Keyword(s):  
Steel Fiber ◽  
Volume Fraction ◽  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
Lightweight Aggregate Concrete ◽  
Fiber Reinforced ◽  
Aggregate Concrete ◽  
Binder Ratio ◽  
Water To Binder Ratio

Steel fiber reinforced lightweight-aggregate concrete (SFRLAC) has many advantages applied in structural engineering. In this paper, the autogenous shrinkage and drying shrinkage of SFRLAC for up to 270 days were measured, considering the effects of types of coarse and fine aggregates with the changes of water-to-binder ratio and volume fraction of steel fiber, respectively. The properties of mix workability, apparent density, and compressive strength of SFRLAC were also reported and discussed in relation to above factors. Test results show that the development of autogenous and drying shrinkage of SFRLAC was fast within 28 days and tended to be steady after 90 days. The development of autogenous shrinkage of SFRLAC reduced with the increasing water-to-binder ratio and by using the expanded shale with higher soundness and good water absorption, especially at early age within 28 days; the later drying shrinkage was reduced and the development of drying shrinkage was slowed down with the increasing volume fraction of steel fiber obviously; manufactured sand led to less autogenous shrinkage but greater drying shrinkage than fine lightweight aggregate in SFRLAC. The regularities of autogenous shrinkage and drying shrinkage of SFRLAC expressed as the series of hyperbola are analyzed.

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