Academic excellence for business and the professions

Student: Faezeh Faghih

Supervisor: Prof. Ashraf Ayoub

Structural Behaviour of High

Performance Materials

Outline

• Steel Fiber Reinforced Concrete (SFRC)

• Reactive Powder Concrete (RPC)

• Carbon Nanofiber (CNF) Reinforced Concrete

FRC material

Research plan

FE Analysis

SFRC

End-hooked Twisted Straight

• Dimensions : Micro-Scale/Macro-Scale

• Volume Percentage (Vf)

• Shape

Outline

Material Properties

SFRC

• Increased tensile strength

• Sub-horizontal post-peak tensile branch

• Increased flexural strength

Introduction

Cement matrix optimisation

RPC

• Elimination of coarse aggregate

• Selection of micro to nano sized particles, e.g. silica

fume, glass powder.

High packing density

Ultra-high

compressive strength Very brittle behaviour Tensile strength;

with fibers

150-250 MPa 10-15 MPa Add steel fibers

Introduction

RPC

Introduction

RPC

• Higher flexural and shear capacity of members

• Crack control due to steel fibers

• Large ductile capacity

Structural Performance

• Unfavourable cost to performance efficiency

• Possible brittle behaviour

Issues

Introduction

CNT/CNF

Fiber Diameter Elastic Modulus

Tensile Strength

Cost

SWCNT 0.3-2 nm 1-1.4 TPa 60 GPa

~£110/g

MWCNT 20-80 nm ~£50/g

CNF 60-200 nm 400 GPa 7 Gpa ~ £0.34/g

CNF

SWCNT

MWCNT

Introduction

Introduction

Concrete is made of C-S-H- nano-structured composite

Concrete properties exist in multiple length scale:

Nano

Micro

Macro

Properties of each scale is derived from those of the

next smaller scale

CNT/CNFRC

Dispersion Issue

Material Properties

•Decreased the shrinkage cracking

•Increased compressive strength (25%-Vf= 2% CNF)

•Increased Young’s modulus (68%-75% )

•Increased flexural strength (50%-80%-250%)- (Vf = 0.05%-0.1%-

1.0%)

•Surface modification of fibers

•Using silica fume

•Using superplasticizer in combination with sonication

Introduction

CNT/CNFRC

Self Health Monitoring (SHM)

• Smart concrete: Electric conductive concrete that has

strain sensing of damage

• The need for embedding sensors is eliminated

• Transforms the structures themselves into infinite sets of

potential continuous sensors

Structural performance – Short column

Introduction

• CNFRC: Ultimate capacity (31%), Deflection (35%),

Ductility (35.1%) higher than RC.

Steel Composite (SC) wall

Sandwich system - Double steel-plate infilled with

concrete

Submerged tube tunnel

Offshore structures

Nuclear power plants

Super-high rise building shear walls and cores

Introduction

FE Analysis

0

50

100

150

200

250

300

0 10 20 30 40

Load

(kN

)

Deflection (mm)

A21

0

20

40

60

80

100

120

140

160

180

200

0 5 10 15 20 25 30 35

Load

(kN

)

Deflection (mm)

R13-1 R13-2 R13C FE

SFRC

RPC

CNFRC

FE Analysis

FE Analysis

0

10

20

30

40

50

60

70

80

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

Load

(K

ips)

Displacment (inch)

SCCNFC

Experiment

FEAPpv

CNFRC

0

50

100

150

200

250

0 0.5 1 1.5 2

Load

(K

ips)

Deflection (inch)

SP1-5

Experiment

FE

FE Analysis

SC Beam

0

100

200

300

400

500

600

0 0.5 1 1.5 2 2.5 3

Load

(K

ips)

Displacement (in.)

SC-Experiment

SC-SF2%

SC-SF1%

SC-RPC-2

SC-CNF

FE Analysis

SC Beam

• CNF concrete material test

• SHM monitoring of CNF Concrete

• CNF concrete structural beam tests

Experiment

• Develop and validate material model based on experiment results for the CNF concrete

• Study structural performance of SC Walls with various FRC materials

FE Analysis

Research Plan

Academic excellence for business and the professions

Thank you!