ABSTRACT
The question is: are we good enough in asking for specifications that would give us a better concrete or, alternatively, are we asking for the right specifications at all? At the current stage of development, certainly our answer is 'not enough' (Figure 2.1). For example, concrete is typically ordered by strength requirements, say 30 MPa or 50 MPa at a certain age. This is because the specimen strength is quantifiable and easily measured at the production stage for quality control and assurance. Similarly, it is logically possible to ask the supplier for a concrete whose performance would last for 500 years or 100 years. How do we ask such a question, and even if we get a concrete that is certified for 500 years of life, how can we be sure of its durability? What if the environmental conditions change with
time? We need to establish a system that answers these questions and also helps us to ask better questions in our pursuit of making a higherperformance concrete. In this chapter, we will explore the requirements for material design and methods of evaluating time-dependent concrete performance that need to be enforced to produce durable concrete in the real world. The mechanics of how those requirements are actually implemented or enforced in the concrete design and technology community, however, generally require a socio-engineering and socio-economical outlook on the problem. Those who are interested in this issue are invited to turn to Chapter 8.
