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THE 20TH ENGINEERS’ INTERNATIONAL CONFERENCE

Tom Mboya Labour College, Kisumu, Kenya

8 – 10 May, 2013

DESIGN FOR STRENGTH OR DURABILITY

G.Nganga, M.Alexander, H.Beushausen and S.Mumenya

IEK CONFERENCE

9TH MAY 2013

Outline

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IntroductionThe South African durability index (DI) performance-based approach

The Gauteng Freeway Improvement Project (GFIP)

The design for durability in KenyaConclusion

Introduction

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Lack of durability in reinforced concrete structures due to corrosion.

The main approach in control of quality of reinforced concrete structures is through a measure of strength.

However, the durability of reinforced concrete structures is dependent on penetrability of the concrete cover.

Strength is therefore an inadequate quality control criterion and to ensure durability the penetrability and thickness of the concrete cover should be verified.

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Durability Index Tests

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The three durability index tests PermeabilityOxygen Permeability Index test (OPI)

Sorptivity Water Sorptivity Index test (WSI)

Conductivity Chloride Conductivity Index test (CCI)

Durability Index Approach (Contd.........)

The application of the test in performance-based design

The development of the durability index test approach in performance specifications

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Gauteng Freeway Improvement Project

Implementation of the durability index performance approach in the GFIP

Improvement of durability index performance-based specifications

Design for Durability in Kenya

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Design for durability in reinforced concrete structures in Kenya

Approaches that can be adapted from the South African durability index performance-based approach.

Design for Durability in Kenya (Contd.........)

BS 8110 Part 1, 1997 Section 2.1.3 Durability, workmanship and materials

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Spacer Blocks

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Conclusion

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Quality control and specifications for spacer blocks

Mix design for durability, not for strength onlyNeed for service life prediction as a

requirement in engineering practice. DI approach can be modified accordingly in

order to develop a Service Life Prediction Model for Kenyan environment.

Adoption of the South African DI approach to design of structures and perform necessary modifications for Kenya’s environment, particularly at the Coastal region.

THANK YOU

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