Topic
Cement
About: Cement is a research topic. Over the lifetime, 68440 publications have been published within this topic receiving 829356 citations.
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TL;DR: In this article, the transport properties of cement mortar with graphene nanoplatelet (GNP) were investigated experimentally in the presence of a low cost carbon-based nano-sheet, which was added to mortar at contents of 0, 2.5, 5.0 and 7.5%.
228 citations
TL;DR: A model for the structure and bonding mechanism of the cement has the following major features: within the secretory pathway of cement gland cells, the electrostatic association of the oppositely charged proteins and divalent cations condense the cement proteins into dehydrated secretory granules; and after secretion, covalent crosslinking through oxidative coupling of DOPA gradually solidifies the continuous phase of the concrete to set the porous structure.
Abstract: Phragmatopoma californica is a marine polychaete that builds protective tubes by joining bits of shell and sand grains with a secreted proteinaceous cement. The cement forms a solid foam (closed cells) via covalent crosslinking, as revealed by electron and laser scanning confocal microscopy. The cement contains extractable calcium and magnesium, and non-extractable phosphorus. Amino acid analysis demonstrated that the phosphorus is in the form of phosphoserine and that >90% of serine in the cement (i.e. 28 mol% of residues) is phosphorylated. In addition to previously identified basic proteins, the cement contains a highly acidic polyphosphoserine protein as a major component. We propose a model for the structure and bonding mechanism of the cement that has the following major features: (1) within the secretory pathway of cement gland cells, the electrostatic association of the oppositely charged proteins and divalent cations (Ca2+ and Mg2+) condense the cement proteins into dehydrated secretory granules; (2) the condensation of the cement leads to the separation of the solution into two aqueous phases (complex coacervation) that creates the closed cell foam structure of the cement; (3) rehydration of the condensed cement granules after deposition onto tube particles contributes to the displacement of water from the mineral substrate to facilitate underwater adhesion; and (4) after secretion, covalent cross-linking through oxidative coupling of DOPA gradually solidifies the continuous phase of the cement to set the porous structure.
228 citations
TL;DR: In this article, the authors present the bases for a calculation of the compounds present in portland cement from chemical analysis, using both arithmetic and diagrammatical methods for such a calculation.
Abstract: The bases for a calculation of the compounds present in portland cement from chemical analysis are presented. Arithmetical and diagrammatical methods are given for such a calculation. It is well recognized that the compounds formed from oxides during cement production determine concrete properties. This paper is seminal in permitting the determination of the actual compounds present in a Portland cement based on an oxide analysis.
228 citations
TL;DR: In this article, a hydration kinetics model for Portland cement is formulated based on thermodynamics of multiphase porous media, and the mechanism of cement hydration is discussed based on literature review.
227 citations
TL;DR: In this article, an evaluation of environmental impacts of geopolymer containing fly ash and silica fume is conducted by benchmarking the environmental impact of three concrete mixes against the conventional cement concrete.
227 citations