Behavior study of NC and HSC RCCs confined by GRP casing and CFRP wrapping

Fathollah Sajedi,Mahdi Shariati 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.30 No.5

This paper presents the results of axial compression testing and numerical modeling on reinforced concrete columns (RCC) with normal concrete (NC) and high-strength concrete (HSC), RCC confined by glass-fiber reinforced plastic pipes (GRP) casing as well as carbon fiber reinforced polymer (CFRP), The major parameters evaluated in the experiments were the effects of concrete type, GRP casing and CFRP wrapping, as well as the number of CFRP layers. 12 cylindrical RCC (150×600 mm) were prepared and divided into two groups, NC and HSC. Each group was divided into two parts; with and without GRP casing. In each part, one column was without CFRP strengthening layer, a column was wrapped with one CFRP layer and another column with two CFRP layers. All columns were tested under concentrated compression load. Numerical modeling was performed using ABAQUS software and the results of which were compared with experimental findings. A good agreement was found between the results. Results indicated that the utilization of CFRP wrapping and GRP casing improved compression capacity and ductility of RCC. The addition of one and two layer-FRP wrapping increased capacity in the NC group to an average of 18.5% and 26.5% and in the HSC group to an average of 10.2% and 24.8%. Meanwhile, the utilization of GRP casing increased the capacity of the columns by 3 times in the NC group and 2.38 times in the HSC group. The results indicated that although both CFRP wrapping and GRP casing increased confinement, the GRP casing gave more increase capacity and ductility of the RCC due to higher confinement. Furthermore, the confinement effect was higher on NC group.

Investigating the effect of using three pozzolans separately and in combination on the properties of self-compacting concrete

Orak, Milad,Sajedi, Fathollah Techno-Press 2021 Advances in nano research Vol.11 No.2

Today, the tendency to use self-compacting concrete (SCC) is expanding because of its significant benefits. In this study, SCC was made by using native materials and then different pozzolans were replaced instead of a part of cement and the rheological and mechanical properties and microstructure of the concrete were investigated. The pozzolans containing of metakaolin (15%, 25% and 35%), silica fume (6%, 12% and 18%) and fly ash (20%, 35% and 50%) were replaced instead of a part of cement separately or simultaneously. Self-compaction tests including slump flow, T500, L-box, U-box, and J-ring as well as mechanical tests including compressive strength, splitting tensile strength, and static modulus of elasticity were performed on the specimens. The results showed that the pozzolans improved the microstructure of the SCC and the secondary reactions improved the mechanical properties of the concrete containing the pozzolans at older ages than the reference concrete. At 15% replacement, metakaolin increased the 180-day compressive strength up to 106 MPa that was about 18% more than reference concrete. In ternary mixtures the maximum and minimum rate were 29% and 19%, respectively, and in quaternary mixtures the rates were significant and increased up to 46%, while the rate for reference concrete was 20%. This significant growth was probably due to the secondary reaction of pozzolans with calcium hydroxide residue from cement hydration.

Evaluation and comparison of GRP and FRP applications on the behavior of RCCs made of NC and HSC

Mohsen Shafieinia,Fathollah Sajedi 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.5

This paper presents the results of axial pressure testing on reinforced concrete columns (RCCs) filled with confined normal concrete (NC) and high-strength concrete (HSC) using glass-fiber reinforced plastic pipes (GRP) casing as well as fiber reinforced polymer (FRP). This study aims to evaluate the behavior and mechanical properties of columns confined with GRP casing and FRP wrapping under pressure loads. The major parameters in the experiments were the type of concrete, the effect of GRP casing and FRP wrapping, as well as the number of FRP layers. 12 cylindrical RCCs (150*600) mm were prepared and divided into two groups, NC and HSC, and each group was divided into two parts. In each part, one column was without FRP strengthening layer, a column was wrapped with one FRP layer and another column with two FRP layers. All columns were tested under concentrated compression load. The results of the study showed that the utilization of FRP wrapping and GRP casing improved compression capacity and ductility of RCCs. The addition of one and two layers-FRP wrapping increased compression capacity in the NC group to an average of 18.5% and 26.5% and to an average of 10.2% and 24.8% in the HSC group. Meanwhile, the utilization of GRP casing increased the compression capacity of the columns by 4 times in the NC group and 3.38 times in the HSC group. The results indicated that although both FRP wrapping and GRP casing result in confinement, the GRP casing resulted in increased compression capacity and ductility of the RCCs due to higher confinement. Furthermore, the confinement effect was higher on columns made with NC.

A review on pavement porous concrete using recycled waste materials

Toghroli, Ali,Shariati, Mahdi,Sajedi, Fathollah,Ibrahim, Zainah,Koting, Suhana,Mohamad, Edy Tonnizam,Khorami, Majid 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.4

Pavements porous concrete is a noble structure design in the urban management development generally enabling water to be permeated within its structure. It has also capable in the same time to cater dynamic loading. During the technology development, the quality and quantity of waste materials have led to a waste disposal crisis. Using recycled materials (secondary) instead of virgin ones (primary) have reduced landfill pressure and extraction demanding. This study has reviewed the waste materials (Recycled crushed glass (RCG), Steel slag, Steel fiber, Tires, Plastics, Recycled asphalt) used in the pavement porous concretes and report their respective mechanical, durability and permeability functions. Waste material usage in the partial cement replacement will cause the concrete production cost to be reduced; also, the concretes' mechanical features have slightly affected to eliminate the disposal waste materials defects and to use cement in Portland cement (PC) production. While the cement has been replaced by different industrial wastes, the compressive strength, flexural strength, split tensile strength and different PC permeability mixes have depended on the waste materials' type applied in PC production.

A review on pavement porous concrete using recycled waste materials

Ali Toghroli,Mahdi Shariati,Fathollah Sajedi,Zainah Ibrahim,Suhana Koting,Edy Tonnizam Mohamad,Majid Khorami 국제구조공학회 2018 Smart Structures and Systems, An International Jou Vol.22 No.4

Pavements porous concrete is a noble structure design in the urban management development generally enabling water to be permeated within its structure. It has also capable in the same time to cater dynamic loading. During the technology development, the quality and quantity of waste materials have led to a waste disposal crisis. Using recycled materials (secondary) instead of virgin ones (primary) have reduced landfill pressure and extraction demanding. This study has reviewed the waste materials (Recycled crushed glass (RCG), Steel slag, Steel fiber, Tires, Plastics, Recycled asphalt) used in the pavement porous concretes and report their respective mechanical, durability and permeability functions. Waste material usage in the partial cement replacement will cause the concrete production cost to be reduced; also, the concretes’ mechanical features have slightly affected to eliminate the disposal waste materials defects and to use cement in Portland cement (PC) production. While the cement has been replaced by different industrial wastes, the compressive strength, flexural strength, split tensile strength and different PC permeability mixes have depended on the waste materials’ type applied in PC production.

Application of polymer, silica-fume and crushed rubber in the production of Pervious concrete

Diyuan Li,Ali Toghroli,Mahdi Shariati,Fathollah Sajedi,Dieu Tien Bui,Peiman Kianmehr,Edy Tonnizam Mohamad,Majid Khorami 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.2

chieving a pervious concrete (PC) with appropriate physical and mechanical properties used in pavement have been strongly investigated through the use of different materials specifically from the global waste materials of the populated areas. Discarded tires and the rubber tire particles have been currently manufactured as the recycled waste materials. In the current study, the combination of polymer, silica fume and rubber aggregates from rubber tire particles have been used to obtain an optimized PC resulting that the PC with silica fume, polymer and rubber aggregate replacement to mineral aggregate has greater compressive and flexural strength. The related flexural and compressive strength of the produced PC has been increased 31% and 18% compared to the mineral PC concrete, also, the impact resistance has been progressed 8% compared to the mineral aggregate PC and the permeability with Open Graded Fraction Course standard (OGFC). While the manufactured PC has significantly reduced the elasticity modulus of usual pervious concrete, the impact resistance has been remarkably improved.