Efficiency of self-healing cementitious materials with encapsulated polyurethane to reduce water ingress through cracks

B Van Belleghem,N De Belie,K Van Tittelboom

doi:10.3989/mc.2018.05917

Abstract

Cracks in reinforced concrete elements can cause major durability issues due do the accelerated ingress of aggressive substances. In this study, repair of cracks was addressed by incorporating encapsulated polyurethane based healing agents in the cementitious material as an autonomous healing mechanism. Capillary sorption tests showed that a high viscosity healing agent could reduce the water ingress in cracked mortar, but a large scatter in the results was found, resulting in a large range of healing efficiencies (18 – 108%). The low viscosity polyurethane showed a more complete and consistent crack healing. Healing efficiencies ranging from 95 to 124% were observed (crack width up to 295 μm). The proposed healing mechanism is very effective in blocking the ingress of water. This will enhance the durability of cementitious materials and consequently extend their lifetime.

Highlights

Capillary sorption tests showed that a high viscosity healing agent could reduce the water ingress in cracked mortar, but a large scatter in the results was found, resulting in a large range of healing efficiencies (18 – 108%)
By the mid-20th century a huge amount of reinforced concrete structures were built based on the available design codes
The presence of cracks in cementitious materials has a detrimental influence on the ingress of aggressive substances

Summary

Introduction

Capillary sorption tests showed that a high viscosity healing agent could reduce the water ingress in cracked mortar, but a large scatter in the results was found, resulting in a large range of healing efficiencies (18 – 108%). The proposed healing mechanism is very effective in blocking the ingress of water This will enhance the durability of cementitious materials and extend their lifetime. RESUMEN: Eficiencia de materiales cementíceos autocurados con poliuretano encapsulado para reducir el ingreso de agua a través de fisuras. In the late 20th century a lot of concrete structures showed major deterioration due to durability problems. This caused a lot of repair and rehabilitation works on existing structures which had huge economic implications. A lot of reinforced concrete structures do not reach this lifetime without major repair works. The major cause for a lot of durability problems is the appearance of cracks during the lifetime of the structure. Aggressive substances can penetrate much faster in the concrete and cause rapid deterioration

Methods

Results

Conclusion