Assessment of the contribution of blended cement to the concrete durability

2021 ◽  
Author(s):  
Vendula Davidová ◽  
Pavel Reiterman
1989 ◽  
Vol 176 ◽  
Author(s):  
Rosemarie Atabek ◽  
Pascal Bouniol ◽  
Eliane Revertegat ◽  
Jean Oliver ◽  
Philippe Gegout ◽  
...  

ABSTRACTAn overview of the different problems to be solved for waste form disposal in a shallow-land burial site is presented. Examples of cementbased materials used to immobilize concentrates are given in relation to cement chemistry. Experimental studies, undertaken to assess concrete durability, obviously indicate that pH is the starting parameter of chemical degradation reactions. It is found that blended cement (CLC) has a better cesium retention ability and a stronger resistance to chloride and sulfate attack than Portland cement.


1988 ◽  
Vol 137 ◽  
Author(s):  
Della M. Roy

AbstractPermeabilities to water and diffusion of ionic species in cementitious grouts, pastes and mortars are important keys to concrete durability. Investigations have been made of numerous materials containing portland and blended cements, and those with fine-grained filler, at room temperature and after prolonged curing at several elevated temperatures up to 90°C. These constitute part of studies of fundamental material relationships performed in order to address the question of long-term durability. In general, the permeabilities of the materials have been found to be low [many <10−8 Darcy (10−13 m·s−1)] after curing for 28 days or longer at temperatures up to 60°C. The results obtained at 90°C are somewhat more complex. In some sets of studies of blended cement pastes with w/c varying from 0.30 to 0.60 and cured at temperatures up to 90°C the more open-pore structure (at the elevated temperature and higher w/c) as evident from SEM microstructural studies as well as mercury porosimetry are generally correlated also with a higher permeability to liquid. The degree of bonding and permeability evident in paste or mortar/rock interfacial studies present somewhat more conflicting results. The bond strength (tensile mode) has been shown to be improved in some materials with increased temperature. The results of permeability studies of paste/rock couples show examples with similar low permeabilities, and some with increased permeability with temperature.Ionic diffusion studies also bring important bearing to understanding the effect of pore structure. The best interrelationships between chloride diffusion and pore structure appear to relate diffusion rate to median pore size. Similar results were found with “chloride permeability” test.


Author(s):  
Dan Georgescu ◽  
Radu Vacareanu ◽  
Alexandru Aldea ◽  
Adelina Apostu ◽  
Cristian Arion ◽  
...  

This article presents a method to assess the sustainability of concrete based on three elements: service life, performance and environmental impact. The method proposes - to achieve similar performance and service life times, regardless of the component materials used, so that the sustainability assessment ultimately depends on the environmental impact criterion. To this end, specific experimental methods are used to determine the performance of concrete in terms of compressive strength and carbonation resistance for concrete cast with two blended cement types. The procedure needed to classify the concrete through carbonation resistance is detailed, in relationship with the performance obtained for compressive strength. The obtained results highlight the concrete formulations to be used to ensure similar performances regardless of the cement type used. In conclusion, the simplicity in the application of the method, which is closely related to the performance approach on concrete durability in the revision proposals of the European standards, is highlighted. The method is also a useful tool to encourage the widespread use in concrete formulation of blended cements with low environmental impact, without reducing the performance or service life time of the constructions.


1998 ◽  
Vol 25 (3) ◽  
pp. 391-400 ◽  
Author(s):  
MDA Thomas ◽  
K Cail ◽  
R D Hooton

The effects of silica fume on the properties of plastic and hardened concrete are now fairly well-established. If properly used, silica fume imparts significant improvement to the strength and durability of concrete; and the availability of this material together with high-range water reducers (superplasticizers) has been largely responsible for the development of high-strength and high-performance concretes. Silica fume has been used in the Canadian cement and concrete industry for over 15 years. Early use was driven by economy, since concrete of a given strength grade could be produced at lower cementitious material content (and cost) if silica fume was incorporated in the mix due to the initial low selling price of the material. The construction boom of the mid to late 1980s saw the exploitation of high-strength silica fume concrete for high-rise construction. By the 1990s, concerns over the deteriorating infrastructure had shifted the focus to concrete durability and silica fume was finding applications in high-performance concrete. Today, silica fume is perhaps the material of choice for engineers designing concrete to withstand aggressive exposure conditions. This paper documents the major developments in the use of silica fume in Canada and discusses the wide range of applications for which the product may be used to beneficial effect.Key words: blended cement, Canada, concrete, high-performance, silica fume.


2015 ◽  
Vol 1 (2) ◽  
pp. 90 ◽  
Author(s):  
Hariharan Harikrishnan ◽  
Shine Kadaikunnan ◽  
Innasimuthu Ganesh Moorthy ◽  
Alexander Ronaldo Anuf ◽  
Karuppiah Ponmurugan ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1003
Author(s):  
Pantharee Kongsat ◽  
Sakprayut Sinthupinyo ◽  
Edgar A. O’Rear ◽  
Thirawudh Pongprayoon

Several types of hematite nanoparticles (α-Fe2O3) have been investigated for their effects on the structure and properties of fly ash (FA) blended cement. All synthesized nanoparticles were found to be of spherical shape, but of different particle sizes ranging from 10 to 195 nm depending on the surfactant used in their preparation. The cement hydration with time showed 1.0% α-Fe2O3 nanoparticles are effective accelerators for FA blended cement. Moreover, adding α-Fe2O3 nanoparticles in FA blended cement enhanced the compressive strength and workability of cement. Nanoparticle size and size distribution were important for optimal filling of various size of pores within the cement structure.


Structures ◽  
2021 ◽  
Vol 29 ◽  
pp. 1898-1910
Author(s):  
Samira Mahmud ◽  
Tanvir Manzur ◽  
Samina Samrose ◽  
Tafannum Torsha

J ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 223-232
Author(s):  
Esperanza Menéndez ◽  
Cristina Argiz ◽  
Miguel Ángel Sanjuán

Ground coal bottom ash is considered a novel material when used in common cement production as a blended cement. This new application must be evaluated by means of the study of its pozzolanic properties. Coal bottom ash, in some countries, is being used as a replacement for natural sand, but in some others, it is disposed of in a landfill, leading thus to environmental problems. The pozzolanic properties of ground coal bottom ash and coal fly ash cements were investigated in order to assess their pozzolanic performance. Proportions of coal fly ash and ground coal bottom ash in the mixes were 100:0, 90:10, 80:20, 50:50, 0:100. Next, multicomponent cements were formulated using 10%, 25% or 35% of ashes. In general, the pozzolanic performance of the ground coal bottom ash is quite similar to that of the coal fly ash. As expected, the pozzolanic reaction of both of them proceeds slowly at early ages, but the reaction rate increases over time. Ground coal bottom ash is a promising novel material with pozzolanic properties which are comparable to that of coal fly ashes. Then, coal bottom ash subjected to an adequate mechanical grinding is suitable to be used to produce common coal-ash cements.


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