2.4.3.1 Introduction The properties that differentiate SCC from conventional concrete are those of the fresh concrete. The required workability for casting concrete depends on the type of construction, selected placement and consolidation methods, complexity of the formwork, and structural design details that affect the degree of congestion of the reinforcement. Table 2.3 Test properties and […]

The basic ingredients used to make SCC, such as cement, supplementary cementing materials, aggregates, chemical admixtures, are the same as those used in making conventional concrete. However, SCC mix constituents and their proportions are to be carefully selected so as to achieve a concrete with lower rheological shear stress and viscosity that would remain homogenous […]

2.4.1 Introduction Self-consolidating concrete (SCC) is highly flowable, nonsegregating concrete that can spread into place, fill the formwork, and encapsulate the reinforcement without any mechanical consolidation. It has also been described as self-compacting concrete, self-placing concrete, and self-leveling concrete, which are subsets of SCC [135]. SCC was initially developed to ensure proper consolidation in applications […]

Concrete is a non-combustible material and has good fire resistant property, and is often used to protect steel from the effects of fire. However, concrete is damaged by exposure to high temperatures and will suffer loss of strength, cracking and spalling. Hydrated Portland cement contains a considerable portion of free calcium hydroxide, which decomposes above […]

Wear can be classified into three catalogues: abrasion, erosion and cavitation. Wear refers to repeated rubbing or frictional process, which is usually in connection with traffic wear on pavements and industrial floors. Erosion is the abrasive action of fluids and suspended solids. It is a special case of abrasion and occurs in water-supply installations such […]

The frost resistance of concrete is of considerable importance in areas where freezing happens during the winter. Unprotected cement pastes dilate as they are frozen, which results in internal tensile stresses and cracking. Several mechanisms have been proposed to explain the paste behaviour during freezing: generation of hydraulic pressure by ice formation, volume increase (9%) […]

The pore solution of a fully hydrated Portland cement usually has a pH over 13 and consists mainly of alkali hydroxides. The high pH results in the formation of a passive layer on the surface of steel reinforcement in the concrete, which is very dense, impenetrable film preventing the further corrosion of the steel. However, […]

It is well known that chlorides cause the corrosion of steels in concrete, while high concentration of calcium chloride also deteriorates concrete very quickly. Hydrated monochloroaluminate (C3A. CaCl2.xH2O) is always identified in calcium chloride attacked cement concrete. However, it cannot be regarded as the main cause of deterioration because this salt forms in cement pastes, […]

The expansion and cracking of concrete caused by alkali-aggregate reaction was first studied in the early 1930’s. There are two types of alkali-aggregate reaction, which can lead to cracking of concrete: (a) alkali-silica reaction (ASR) and (b) alkali-carbonate reaction (ACR). ASC is a chemical reaction within concrete between specific siliceous constituents, which sometimes occur in […]

Sulfate attack on concrete is a relatively rare but complex damage phenomenon caused by exposure of concrete products or structures to an excessive amount of sulfate from internal or external sources [97]. External sulphate attack is due to penetration of sulfates in solution, in groundwater for example, into the concrete from outside; while internal sulphate […]