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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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Journal ArticleDOI
TL;DR: Hydxyapatite-added glass ionomer cement has a potential as a reliable restorative material with improved fracture toughness, long-term bonding to dentin and unimpeded ability of sustained fluoride release.

149 citations

Journal ArticleDOI
TL;DR: For applications where controlled (prompt) setting is more critical than developing high strengths, significant levels of these powder replacements for cement can serve as sustainable, functional alternatives to the oft-employed 100 % OPC products.
Abstract: Developing functional concrete mixtures with less ordinary portland cement (OPC) has been one of the key objectives of the 21st century sustainability movement. While the supplies of many alternatives to OPC (such as fly ash or slag) may be limited, those of limestone and silica powders produced by crushing rocks seem virtually endless. The present study examines the chemical and physical influences of these powders on the rheology, hydration, and setting of cement-based materials via experiments and three-dimensional microstructural modeling. It is shown that both limestone and silica particle surfaces are active templates (sites) for the nucleation and growth of cement hydration products, while the limestone itself is also somewhat soluble, leading to the formation of carboaluminate hydration products. Because the filler particles are incorporated as active members of the percolated backbone that constitutes initial setting of a cement-based system, replacements of up to 50 % of the OPC by either of these powders on a volumetric basis have minimal impact on the initial setting time, and even a paste with only 5 % OPC and 95 % limestone powder by volume achieves initial set within 24 h. While their influence on setting is similar, the limestone and silica powders produce pastes with quite different rheological properties, when substituted at the same volume level. When proceeding from setting to later age strength development, one must also consider the dilution of the system due to cement removal, along with the solubility/reactivity of the filler. However, for applications where controlled (prompt) setting is more critical than developing high strengths, such as mortar tile adhesives, grouts, and renderings, significant levels of these powder replacements for cement can serve as sustainable, functional alternatives to the oft-employed 100 % OPC products.

149 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of three nano-sized powders of the main oxides of cement (nano-SiO2, nano-Al2O3, and nano-FeO3) on the compressive strength and capillary permeability of cement mortars containing silica fume were investigated.
Abstract: In this article, the single, binary and ternary effects of three nano-sized powders of the main oxides of cement (nano-SiO2, nano-Al2O3 and nano-Fe2O3) on the compressive strength and capillary permeability of cement mortars containing silica fume were investigated. The powder amounts were chosen at proportions corresponding to 0.5%, 1.25% and 2.5% of the binder amount. Compressive strength was determined for early age (3- and 7-day), standard age (28-day), and late age (56- and 180-day) mortars, while capillary permeability was determined for 180-day-old mortars only. It was concluded from the experimental results that the type and amount of nano the powders, and mortar production methods had a significant effect on the fresh and hardened properties of cement mortars. The nano-powders used singly or in combination increased the 28-day compressive strength of silica fume-containing mortars by up to 27%, with the exception of nano-SiO2 powder used at a proportion of 2.5%. However, the compressive strength values fluctuated at early and later ages. The best results for compressive strength and capillary permeability at the end of day 180 were obtained with 1.25% nano-Al2O3 powder in single uses, 0.5% nano-SiO2 + nano-Al2O3 powders in binary combinations, and 0.5% in ternary combination. However, it was determined that the interaction between the powders used in binary and ternary combinations led to negative effects on the physical–mechanical properties of the mortars. For this reason, nano-Al2O3 powder and single use were primarily recommended in cases where an increase in the performance of cement-based composites is desired. The findings of the experiments suggested the conclusion that the improvement in the mechanical and physical properties of mortars was caused by the rise in pozzolanic activity induced by the favorable influence of the powders rather than the filler effect.

149 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of various carbonating environments on pore solution composition and on aspects of the pore structure and mineralogy of the carbonated products are reported, and the likely effects of different accelerated carbonation regimes on the corrosion behaviour of steel in concrete are discussed.

149 citations

Journal ArticleDOI
TL;DR: In this article, the performance of lightweight concrete under different w/cm ratio and different cement paste content was compared with self-consolidating lightweight concrete (SCLWC), and the test results indicated that the 91-day compressive strength of SCLWC is up to 56 MPa when cement content is 386 kg/m3 and water content is 150 kg /m3.

149 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20248
20234,852
20228,607
20213,442
20203,929
20194,260