Improving the Mechanical Performance of Shell Precast Concrete Blocks for Coastal Protection Structures of Hydraulic Works

Nguyen Viet Duc

doi:10.48084/etasr.4009

Abstract

Although the use of concrete and reinforced concrete for construction has been widespread, more studies are needed on marine structures exposed directly to corrosive environments to prolong their service life. This paper proposes a new type of shell precast concrete block for coastal structures, studying a beam consisting of 15mm High-Performance Glass Fiber-Reinforced Concrete (HPGFRC) at the bottom and 45mm Traditional Concrete (TC) for the rest of the structure. Steel bar reinforcements were placed at the bottom with a concrete cover of 25mm to avoid abrupt failure. The strength classes of HPGFRC and TC were 60MPa and 30MPa respectively. A reference beam consisting of TC only was also prepared for comparison. The four-point flexural bending test results showed that the first cracking strength of the proposed beam was 20% higher, as HPGFRC performed better on tension than TC. Additionally, HPGFRC's maximum strength was 25% greater than TC's. Furthermore, HPGFRC possessed more durable characteristics such as waterproof grade, abrasion resistance, and shrinkage than TC, promising to protect the reinforcement from the aggressive marine environment and corrosion, prolonging the service life of the structure.

Highlights

Concrete is a versatile material that plays an important role in various construction fields including civil engineering, transportation, irrigation, and marine engineering [1]
This paper proposes the concept of a shell precast concrete block having High-Performance Glass FiberReinforced Concrete (HPGFRC) in its partial cover layer, in combination with Traditional Concrete (TC), to protect the concrete matrix, especially reinforcement, from the aggressive environment
The HPGFRC was at the bottom and the TC was on the top of the beam

Summary

Introduction

Concrete is a versatile material that plays an important role in various construction fields including civil engineering, transportation, irrigation, and marine engineering [1]. The chemical composition of seawater can cause corrosive phenomena to both the cement matrix and the reinforcement of marine structures, reducing their service life [5]. After 1960, the volume of reinforced concrete works in marine environments increased significantly. The actual durability or longevity of reinforced concrete works has been thouroughly studied, and a reinforced concrete structure can be sustainable for over 100 years in non-corrosive environments [9]. In an aggressive marine environment, corrosion of reinforcement and concrete leading to cracks may appear after 10-30 years of use [8]. The actual service life of reinforced concrete structures depends on the level of environmental erosion and the quality of materials used, such as concrete's strength, waterproofing grade, corrosion resistance, cement type, additives, reinforcement type, design quality, etc. The actual service life of reinforced concrete structures depends on the level of environmental erosion and the quality of materials used, such as concrete's strength, waterproofing grade, corrosion resistance, cement type, additives, reinforcement type, design quality, etc. [10]

Methods

Results

Conclusion