Concrete Strength Development

High

Strength

Concrete

High-strength concrete

Definitions

The definition of high-performance concrete is

more controversial.

Mehta and Aitcin used the term, highperformance concrete (HPC) for concrete

mixtures possessing high workability, high

durability and high ultimate strength.

P.K. Mehta and P.J.M. Monteiro, Concrete: Microstructure, Properties, and Materials

High-strength concrete

Definitions

ACI defined high-performance concrete as a

concrete meeting special combinations of

performance and uniformity requirements that

cannot always be achieved routinely using

conventional constituents and normal mixing,

placing, and curing practice.

P.K. Mehta and P.J.M. Monteiro, Concrete: Microstructure, Properties, and Materials

High-strength concrete

Typical Classification

Normal Strength

20-50 MPa

High Strength

50-100 MPa

Ultra High Strength

100-150 MPa

Especial

> 150 MPa

P.K. Mehta and P.J.M. Monteiro, Concrete: Microstructure, Properties, and Materials

High-strength concrete

Microstructure

From the general principles behind the design of

high-strength concrete mixtures, it is apparent

that high strengths are made possible by reducing

porosity, inhomogeneity, and microcracks in the

hydrated cement paste and the transition zone.

P.K. Mehta and P.J.M. Monteiro, Concrete: Microstructure, Properties, and Materials

High-strength concrete

Microstructure

The utilization of fine pozzolanic materials in high-strength

concrete leads to a reduction of the size of the crystalline

compounds, particularly, calcium hydroxide.

Consequently, there is a reduction of the thickness of the

interfacial transition zone in high-strength concrete.

The densification of the interfacial transition zone allows

for efficient load transfer between the cement mortar and

the coarse aggregate, contributing to the strength of the

concrete.

For very high-strength concrete where the matrix is

extremely dense, a weak aggregate may become the

weak link in concrete strength.

P.K....