Lecture

Mechanisms of Carbonation

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Description

This lecture covers the mechanisms of carbonation in cementitious materials, including CO2 diffusion, dissolution, pH buffering, and calcite precipitation. It also discusses the penetration depth of carbonation, buffering capacity, and acid-base reactions.

In MOOC

Sorption and transport in cementitious materials

In the MOOC: “Cement chemistry and sustainable cementitious materials”; you learned how to create more sustainable cementitious materials. But concrete is not an inert rock. It is a dynamic porous material, which can exchange water, gas and ions with its environment. Through physical and chemical interactions, these exchanges can have dramatic consequences: cracks due to shrinkage, reinforcement bars corrosion, spalling, … For a true sustainability, the durability of cementitious materials should not be f

Official source

Related concepts (14)

Calcite sea

A calcite sea is a sea in which low-magnesium calcite is the primary inorganic marine calcium carbonate precipitate. An aragonite sea is the alternate seawater chemistry in which aragonite and high-magnesium calcite are the primary inorganic carbonate precipitates. The Early Paleozoic and the Middle to Late Mesozoic oceans were predominantly calcite seas, whereas the Middle Paleozoic through the Early Mesozoic and the Cenozoic (including today) are characterized by aragonite seas.

Calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite.

Buffer solution

A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an acid or a base aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. In nature, there are many living systems that use buffering for pH regulation.

Carbonate rock

Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolostone), which is composed of mineral dolomite (CaMg(CO3)2). They are usually classified based on texture and grain size. Importantly, carbonate rocks can exist as metamorphic and igneous rocks, too. When recrystallized carbonate rocks are metamorphosed, marble is created.

Aragonite

Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The crystal lattice of aragonite differs from that of calcite, resulting in a different crystal shape, an orthorhombic crystal system with acicular crystal. Repeated twinning results in pseudo-hexagonal forms.

Related lectures (26)

Water Quality Modeling: Kinetics in PHREEQC

Explores water quality modeling, focusing on reaction kinetics, equilibrium constants, and temperature effects, with practical examples of calcite precipitation and iron oxidation.

Water Quality Modelling: EC, Alkalinity, Hardness, Carbonate Chemistry

Explores EC, alkalinity, hardness, and carbonate chemistry in water quality modelling, emphasizing measurement methods and ion relationships.

Buffer Solutions in Biology

Explores buffer solutions in biology, discussing their importance in pH regulation and the preparation of specific pH buffers.

Chemical Equilibria and Reactivity

Explores chemical equilibria, weak acids, buffers, titration curves, and indicators in acid-base reactions.

Water Quality Modelling: Equilibrium Phases