Creep Behaviour of Concrete The magnitude of the creep strains can be higher than the elastic strains on loading, and they therefore often have a highly significant influence on structural behaviour. Also, creep does not appear to tend to a limit, as shown in Fig. 1 for tests of more than 20 years duration. This […]

Stress–strain Behaviour  of Concrete Elasticity of Hardened Cement Paste HCP has a near linear compressive stress–strain relationship for most of its range and therefore a modulus of elasticity can readily be determined from stress–strain data. Water-saturated pastes generally have a slightly higher modulus than dried pastes, indicating that some of the load is carried by

Deformation of concrete results both from environmental effects, such as moisture gain or loss and heat, and from applied stress, both short- and long-term. A general view of the nature of the behaviour is given in Fig. 1, which shows the strain arising from a uniaxial compressive stress applied to concrete in a drying environment.

Successful placing of concrete is not enough. It is necessary to ensure that it comes through the first few days of its life without mishap, so that it goes on to have the required mature properties. Immediately after placing, before the cement’s initial set the concrete is still in a plastic and at least semi-fluid

Civil engineers are responsible for the production, transport, placing, compacting and curing of fresh concrete. Without adequate attention to all of these the potential hardened properties of the concrete, such as strength and durability, will not be achieved in the finished structural element. It is important to recognise that it is not sufficient simply to

Hardened cement paste (HCP) formed from the hydration of mixtures of Portland cement, admixtures and additions has strength and other properties that could make it suitable for use as a construction material in its own right. However, it suffers from two main drawbacks – high dimensional changes, in particular low modulus, high creep and shrinkage,

In this aritcle, we will briefly discuss some alternatives to Portland cement. These include calcium aluminate cement, which has been in use for a hundred years or so, and some cements that have had more limited use or are currently being developed and are not yet in widespread use. This latter group is of particular

Admixtures are chemicals that are added to concrete during mixing and significantly change its fresh, early age or hardened state to economic or physical advantage. They are usually defined as being added at rates of less than 5% by weight of the cement, but the typical range for most types is only 0.3 – 1.5%.

Compressive Strength of Masonry Walls Axial loads Masonry is most effective when resisting axial compressive loads normal to the bedding plane. This is, clearly, the way in which most load-bearing walls function but also the way that arches and tunnels resist load since an inward force on the outside surface of a curved plate structure