Origin and Classification of Aggregates

Origin and Classification of Aggregates Most of the properties of an aggregate derive from its parental rock chemical and mineral composition which affects strength, stiffness, density, pore structure and permeability. Rocks experience geothermal and weathering processes which can produce granular materials in the form of natural gravels and sands, these types of aggregates can be …

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Pervious Concrete

Pervious Concrete Pervious concrete is a type of concrete with a system of interconnected pores allowing water to rapidly drain through. Pervious concrete itself is made up of coarse aggregate that is coated by a thin layer of cement paste, holding the system together. While the compressive strength, void content, and permeability tend to vary …

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Types of Chemical Admixtures

admixtures

Admixtures A material other than water, aggregates, or cement that is used as an ingredient of concrete or mortar to control setting and early hardening, workability, or to provide additional cementing properties. Why is admixture used? Over decades, attempts have been made to obtain concrete with certain desired characteristics such as high compressive strength, high …

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Formwork Materials

Formwork

Formwork materials can be classified as: 1. Timber 2. Metals 3. Plastics 1.Timber a. Lumber: Lumber is commonly available material and has excellent strength, weight and cost factor. Lumber is classified as: • Boards: 1 to 1.5 inches thick, 2 or more inches width • Dimensions: 2 to 4 inch thick, any width. • Timbers: …

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Carbonation and Corrosion

Carbonation and Corrosion

Carbonation is the term used to describe the effect of carbon dioxide on a material. The phenomenon rarely leads to structural problems but carbonation-induced corrosion can lead to unsightly spalling on structures. The repair costs, for example to multi-storey office development façades, can be considerable. Carbonation of cementitious materials results in a lowering of the …

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Concrete Aggregates: Effects and Classification

concrete aggregate

Aggregates: Effects and Classification Aggregates constitute a skeleton of concrete. Approximately three-quarters of the volume of conventional concrete is occupied by aggregate. It is inevitable that a constituent occupying such a large percentage of the mass should contribute important properties to both the fresh and hardened product. Aggregate is usually viewed as an inert dispersion …

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