Search results
Results from the WOW.Com Content Network
These pozzolanic reaction products fill in pores and result in a refining of the pore size distribution or pore structure. This results in a lowered permeability of the binder. The contribution of the pozzolanic reaction to cement strength is usually developed at later curing stages, depending on the pozzolanic activity.
Pozzolana from Mount Vesuvius volcano, Italy. Pozzolana or pozzuolana (/ ˌ p ɒ t s (w) ə ˈ l ɑː n ə / POT-s(w)ə-LAH-nə, Italian: [potts(w)oˈlaːna]), also known as pozzolanic ash (Latin: pulvis puteolanus), is a natural siliceous or siliceous-aluminous material which reacts with calcium hydroxide in the presence of water at room temperature (cf. pozzolanic reaction).
The pozzolanic reaction is the chemical reaction that occurs in portland cement upon the addition of pozzolans. It is the main reaction involved in the Roman concrete invented in Ancient Rome and used to build, for example, the Pantheon. The pozzolanic reaction converts a silica-rich precursor with no cementing properties, to a calcium silicate ...
Portland pozzolan cement includes fly ash cement, since fly ash is a pozzolan, but also includes cements made from other natural or artificial pozzolans. In countries where volcanic ashes are available (e.g., Italy, Chile, Mexico, the Philippines), these cements are often the most common form in use. The maximum replacement ratios are generally ...
Compared to using Portland cement, the resulting concrete-mix using EMC does not require a higher "total cementitious content" to meet strength-development requirements. In testing by BASF, the 28-day strength-development for 55% replacement of Portland cement by a natural pozzolanic EMC was 14,000 psi / 96.5 MPa (i.e. > C95). This comprised a ...
Construction block made from hempcrete Illustration of hemp concrete carbon emissions and sequestration, with a net emissions balance indicating carbon negativity. Hempcrete or hemplime is biocomposite material, a mixture of hemp hurds and lime, [1] sand, or pozzolans, which is used as a material for construction and insulation. [2]
Eco-Cement is a brand-name for a type of cement which incorporates reactive magnesia (sometimes called caustic calcined magnesia or magnesium oxide, MgO), another hydraulic cement such as Portland cement, and optionally pozzolans and industrial by-products, to reduce the environmental impact relative to conventional cement.
The pozzolanic reaction, which is specific to siliceous and/or aluminous additions (fly ash, blast-furnace slag, silica fume, calcined clay, etc.) in composite cement, can strengthen the continuous hydration of cement grains in terms of long-term CSH development and, as a result, a certain degree of autogenous self-healing.