High-Early-Strength Concrete Definition
High-Early-Strength Concrete is a term under the category of High Performance Concrete, it is also known as fast-track concrete that means it just takes a few hours (or even minutes) to several days to achieve its specified strength.The time period is shorter than normal concrete. Except for the traditional concrete components concreting practices, the performance of high-early-strength also need some special materials or techniques.
High-Early-Strength Concrete Mix Design
Based on some experimental data, people often choose one or a combination of Type III or HE high-early-strength cement, High cement content (400 to 600 kg/m3 or 675 to 1000 lb/yd3), Low water-cementing materials ratio (0.20 to 0.45 by mass), Higher freshly mixed concrete temperature, Higher curing temperature, Chemical admixtures, Silica fume (or other supplementary cementing materials), Steam or autoclave curing, Insulation to retain heat of hydration, Special rapid hardening cements to obtain the high early strength. It also should take the age at which the specified strength must be achieved and the job conditions into consideration when you decide the final mix design of the high early strength concrete. Additionally, when we compound the mixtures of high early strength concrete, the properties of the strength development, durability, early stiffening, autogenous shrinkage, drying shrinkage, temperature rise, etc are all that we should consider its compatibility with the project. Some special curing procedures, such as fogging, may be needed to control plastic shrinkage cracking.
High-Early-Strength Concrete Uses
As a type of high performance concrete, high early strength concrete has been recognized in many construction fields such as in prestressed concrete to allow for early stressing, in precast concrete for rapid production elements, in high speed cast-in-place construction, in cold weather construction, in rapid repair of pavements to reduce traffic downtime, in fast-track paving, etc. And it has showed the outstanding construction performance in above projects. The uses of high early strength has speed up the construction period and made the project put into operation ahead of schedule.Take the fast-track paving for example, after the concrete is placed, the high early strength mixtures can allow the traffic open within a few hours.