Performance based specifications for durability of mass concrete blocks subjected to harsh Arabian Gulf marine environment

Concrete structures in the Eastern region of Saudi Arabia are exposed to the harsh Arabian Gulf environment, and they suffer from deterioration due to accelerated corrosion of the reinforcing steel resulting in reduced service life. The service life of reinforced concrete structures in this environment is strongly affected by the quality of concrete. The resistances of concrete to chloride penetration, the chloride threshold for corrosion initiation and corrosion rate of the reinforcing steel are critical in ensuring long-term durability of concrete structures. In order to ensure that the concrete functions in the harsh environment for which it is expected to meet the service life requirement, the concrete must be designed for durability performance. A prescriptive concrete specification emphasizing on limits on mix parameters is generally ineffective for durability issues. A performance based specification based on concrete quality represented by durability indices and compliance criteria measured on cast-in-place concrete provides a framework for the contractor and ready-mix concrete supplier to produce a structure meeting the stipulated service life by the client. This paper presents the results of experimental investigations conducted for mass-concrete blocks used in the quay walls off the coastline on a reclaimed land. For long-term durability, a concrete mix in which 50% and 70% of cement was replaced by ground blast furnace slag was used to cater for the durability performance requirements.