FraMCoS 7 2010 Jeju, South Korea

Durability of SHCC under imposed strain

Strain hardening cement-based composites form a group of novel building materials with prom- ising properties for more durable and sustainable construction. In normal cement concrete or mortar the strain capacity under tensile stress is very limited. The sum of thermal,…

First page of: Durability of SHCC under imposed strain
Year 2010
File Size 1 MB
Download PDF (1 MB)

Abstract

Strain hardening cement-based composites form a group of novel building materials with prom- ising properties for more durable and sustainable construction. In normal cement concrete or mortar the strain capacity under tensile stress is very limited. The sum of thermal, hygral, and mechanical stresses is in most practical cases sufficient to create surface cracks. As cracks are known to be preferential paths for ingress of aggressive compounds such as chlorides or sulfates into concrete service life of reinforced concrete structures is often significantly reduced by crack formation. The ultimate strain capacity of SHCC is with more than 3% high enough to support most stresses induced by combined loads without macro-crack formation. The pene- tration of water into SHCC before loading and after imposed strain has been measured by means of neutron radiography. It can be shown that multi-crack formation facilitates water penetration although micro-cracks are formed only. With respect to durability and service life a maximum allowable strain has to be determined. Micro-cracks formed in water repellent SHCC do not absorb liquid water; that means higher strain is admissi- ble in this type of SHCC without reduction of service life of reinforced structural elements.