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  2. Types of concrete - Wikipedia

    en.wikipedia.org/wiki/Types_of_concrete

    The parts are in terms of weight – not volume. For example, 1-cubic-foot (0.028 m 3) of concrete would be made using 22 lb (10.0 kg) cement, 10 lb (4.5 kg) water, 41 lb (19 kg) dry sand, 70 lb (32 kg) dry stone (1/2" to 3/4" stone). This would make 1-cubic-foot (0.028 m 3) of concrete and would weigh about 143 lb (65 kg). The sand should be ...

  3. Properties of concrete - Wikipedia

    en.wikipedia.org/wiki/Properties_of_concrete

    All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1] Reinforced concrete is the most common form of concrete.

  4. Concrete category - Wikipedia

    en.wikipedia.org/wiki/Concrete_category

    A concrete category is a pair (C, U) such that. U : C → Set (the category of sets and functions) is a faithful functor. The functor U is to be thought of as a forgetful functor, which assigns to every object of C its "underlying set", and to every morphism in C its "underlying function". It is customary to call the morphisms in a concrete ...

  5. Concrete - Wikipedia

    en.wikipedia.org/wiki/Concrete

    A single concrete block, as used for construction. Concrete is a composite material composed of aggregate bonded together with a fluid cement that cures to a solid over time. Concrete is the second-most-used substance in the world after water, [ 1 ] and is the most widely used building material. [ 2 ] Its usage worldwide, ton for ton, is twice ...

  6. Category (mathematics) - Wikipedia

    en.wikipedia.org/wiki/Category_(mathematics)

    In mathematics, a category (sometimes called an abstract category to distinguish it from a concrete category) is a collection of "objects" that are linked by "arrows". A category has two basic properties: the ability to compose the arrows associatively and the existence of an identity arrow for each object.

  7. Fracture mechanics - Wikipedia

    en.wikipedia.org/wiki/Fracture_mechanics

    Concrete fracture analysis is part of fracture mechanics that studies crack propagation and related failure modes in concrete. [17] As it is widely used in construction, fracture analysis and modes of reinforcement are an important part of the study of concrete, and different concretes are characterized in part by their fracture properties. [ 18 ]

  8. Abstract algebra - Wikipedia

    en.wikipedia.org/wiki/Abstract_algebra

    The permutations of the Rubik's Cube form a group, a fundamental concept within abstract algebra. In mathematics, more specifically algebra, abstract algebra or modern algebra is the study of algebraic structures, which are sets with specific operations acting on their elements. [ 1 ] Algebraic structures include groups, rings, fields, modules ...

  9. Mathematics - Wikipedia

    en.wikipedia.org/wiki/Mathematics

    Mathematics is a field of study that discovers and organizes methods, theories and theorems that are developed and proved for the needs of empirical sciences and mathematics itself. There are many areas of mathematics, which include number theory (the study of numbers), algebra (the study of formulas and related structures), geometry (the study ...