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Calcium silicate hydrate (also shown as C-S-H) is a result of the reaction between the silicate phases of Portland cement and water. This reaction typically is expressed as: 2 Ca 3 SiO 5 + 7 H 2 O → 3 CaO · 2 SiO 2 · 4 H 2 O + 3 Ca(OH) 2 + 173.6 kJ. also written in cement chemist notation, (CCN) as: 2 C 3 S + 7 H → C 3 S 2 H 4 + 3 CH + heat
The cement reacts with the water through a process called concrete hydration [4] that hardens it over several hours to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. [5] This time allows concrete to not only be cast in forms, but also to have a variety of tooled processes performed.
Concrete hardens as a result of the chemical reaction between cement and water (known as hydration and producing heat). For every mass (kilogram, pound, or any unit of weight) of cement (c), about 0.35 mass of water (w) is needed to fully complete the hydration reactions. [1]
Thermal Integrity Profiling (TIP) is a non-destructive testing method used to evaluate the integrity of concrete foundations. It is standardized by ASTM D7949 - Standard Test Methods for Thermal Integrity Profiling of Concrete Deep Foundations. The testing method was first developed in the mid 1990s at the University of South Florida.
Its hydration to phases of the form Ca 2 AlO 3 (OH) · n H 2 O leads to the phenomenon of "flash set" (instantaneous set), and a large amount of heat is generated. To avoid this, Portland-type cements include a small addition of calcium sulfate (typically 4-8%).
Cement hydration and strength development mainly depend on two silicate phases: tricalcium silicate (C 3 S) , and dicalcium silicate (C 2 S) . [1] Upon hydration, the main reaction products are calcium silicate hydrates (C-S-H) and calcium hydroxide Ca(OH) 2, written as CH in the cement chemist notation. C-S-H is the phase playing the role of ...
Mechanical evaluation of the pozzolanic activity is based upon a comparison of the compressive strength of mortar bars containing pozzolans as a partial replacement for Portland cement to reference mortar bars containing only Portland cement as binder. The mortar bars are prepared, cast, cured and tested following a detailed set of prescriptions.
Ettringite is also known as the 'Candlot's salt' in honor of the pioneering work of the French chemist Édouard Candlot (1858-1922) who studied cement hydration and discovered calcium sulfo-aluminates. [7] [8] Henri Louis Le Chatelier also identified AFt phases when he investigated cement hydration products after the discovery of Candlot. [9]