Concrete durability and sustainability as influenced by resistance to fluid ingress and selection of cementitious materials

2010 ◽  
pp. 99-114
Author(s):  
R Hooton
Keyword(s):  
Cementitious Materials ◽  
Concrete Durability ◽  
Selection Of

Using of Untreated Carbon Nanotubes in Cement Compositions

2016 ◽  
Vol 865 ◽  
pp. 6-11 ◽  
Author(s):  
Kateryna Pushkarova ◽  
Maryna Sukhanevych ◽  
Artur Martsikh
Keyword(s):  
Carbon Nanotubes ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Positive Influence ◽  
Mechanical Tests ◽  
Strength Characteristics ◽  
Concrete Durability ◽  
Cement Mortars ◽  
Optimum Decision ◽  
Cement System

One of the most important problem of concrete durability is increasing of waterproofing. Researches are devoted studying of cement mortars modified by carbon nanotubes, dispersed in plasticizers solutions. Were investigated physico-mechanical properties of cement paste, cement-sand mortar into which structure entered untreated carbon nanotubes (production of plant TM "Spetsmash" Kyiv, Ukraine) in various quantity. Were used as plasticizers in cement compositions additives substances of the various chemical nature – naphtaleneformaldehyde, melamineformaldehyde and polycarboxylate. Quantity of untreated nanotubes varied from 0,5%; 1,0% and to 1,5%. Concentration of additives was accepted taking into account recommendations of producers and made about 1% from the weight of cement. Were studied some technological processes of introduction untreated carbon nanotubes in cement system and is shown that the way of introduction of nanomodifiers has essential impact on strength characteristics of cementitious materials. Optimum decision introduction of untreated carbon nanotubes is using its in dispersion plasticizer of the working concentration prepared in an ultrasonic dispergator is established. Results of physico-mechanical tests of cement paste and cement-sand mortar showed positive influence at introduction of untreated carbon nanotubes as cement modifiers on strength characteristics of samples. Resalts is shown that the nanomodifier, used quantity about 1% in solution of lignosulfonate with polycarboxylate and melamineformaldehyde plasticizer has great impact on strength characteristics.

scholarly journals The Effect of Sisal Juice Extract Admixture on Compressive and Flexural Strength of Cement Concrete

2021 ◽  
Vol 11 (2) ◽  
pp. 7041-7046
Author(s):  
M. O. Eloget ◽  
S. O. Abuodha ◽  
M. M. O. Winja
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Cementitious Materials ◽  
Strength Development ◽  
Concrete Durability ◽  
Flexural Test ◽  
Concrete Compressive Strength ◽  
Cement Concrete ◽  
Shrinkage Cracking ◽  
Lower Permeability

The characteristics of concrete are influenced by the ratio of water to cementitious materials (w/c) used in the mixture. An increase in paste quality will yield higher compressive and flexural strength, lower permeability, increased resistance to weathering, improve the bond between concrete and reinforcement, reduced volume change from drying and wetting, and reduced shrinkage cracking tendencies. Admixtures are used to improve the properties of concrete or mortar. The current study investigates the effect of Sisal Juice Extract (SJE) as an admixture on concrete durability. SJE contains unrefined minerals which can be used as organic retarders to increase the rate of strength development at an early age. A total of 84 concrete cubes were produced in 7 sets of 12 samples each. One set was the control mix which had zero SJE content. The remaining sets had varying dosages of SJ namely 5%, 10%, 15%, 20%, 25%, and 30%. Twelve beam specimens were also cast and subjected to the three-point flexural test. To establish the effect on strength of concrete, compressive strength was tested at 7, 14, 28, and 56 days while flexural strength was tested at 28 days. The highest compressive strength was achieved at 5% dosage beyond which a decrease in strength occurred for all the higher dosages.

Nanotechnology Applications in the Construction Industry

2016 ◽  
pp. 111-140 ◽  
Author(s):  
Iman Mansouri ◽  
Elaheh Esmaeili
Keyword(s):  
Construction Industry ◽  
Material Properties ◽  
Construction Materials ◽  
Cementitious Materials ◽  
Extensive Literature ◽  
Current Scenario ◽  
Potential Benefits ◽  
Improved Performance ◽  
Strength And Durability ◽  
Selection Of

Nanotechnology refers to the understanding and manipulation of materials on the nanoscale (<100 nm). This can lead to marked changes in material properties and can result in improved performance and new functionality. Nanomaterials with properties such as corrosion resistance, and strength and durability are of particular interests to construction professionals, because, these properties directly affect the selection of construction materials, erection methods, and on-site handling techniques. Applying nanotechnology to construction, in some cases, may result in visionary and paradigm-breaking advances. The incorporation of nanomaterials can improve structural efficiency, durability and strength of cementitious materials and can thereby assist in improving the quality and longevity of structures. This chapter tries to analyze nanotechnology in the context of construction and explores the current scenario of nanotechnology in the construction industry. In order to identify the potential benefits and existing barriers, an extensive literature review is conducted.

scholarly journals Recent developments in reactivity testing of supplementary cementitious materials

2021 ◽  
Vol 6 ◽  
pp. 131-139
Author(s):  
Prannoy Suraneni
Keyword(s):  
Heat Release ◽  
Calcium Hydroxide ◽  
Bound Water ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Concrete Durability ◽  
Index Test ◽  
Bulk Resistivity ◽  
Amorphous Content ◽  
Two Parameters

Identification and rapid characterization of novel supplementary cementitious materials (SCMs) is a critical need, driven by shortfalls in conventional SCMs. In this study, we present a discussion of recently developed reactivity tests – the R3 test, the modified R3 test, the lime strength test, and the bulk resistivity index test. These tests measure reactivity parameters such as heat release, bound water, calcium hydroxide consumption, strength, and bulk resistivity. All tests can screen inert from reactive materials. To additionally differentiate pozzolanic and latent hydraulic materials, two parameters, for example, calcium hydroxide consumption and heat release, are needed. The influences of SCM bulk chemistry, amorphous content, and fineness on measured reactivity are outlined. Reactivity test outputs can predict strength and durability of cement paste/mortar/concrete; however, caution must be exercised as these properties are influenced by a variety of other factors independent of reactivity. Thoughts are provided on using reactivity tests to screen materials for concrete durability.

Research and Application of Geopolymer Cementitious Material Progress and Review

2013 ◽  
Vol 405-408 ◽  
pp. 2903-2911
Author(s):  
Zhong Wen Ou ◽  
Shang Yong Zhou ◽  
Chun Xia Xu ◽  
Yi Zhang ◽  
Jin Chao Yang ◽  
...  
Keyword(s):  
Large Scale ◽  
Raw Materials ◽  
Cementitious Materials ◽  
Research Field ◽  
Cementitious Material ◽  
Materials Development ◽  
History Of ◽  
Material Progress ◽  
Agent Development ◽  
Selection Of

Study on the geopolymers has been a history of nearly 40 years, because of its huge comparative advantage and attractive prospect, has become a hot research field of international materials.In this paper, based on the history and the present status of geopolymers cementitious materials development, summarized geopolymer cementitious material in the selection of raw materials, the activation agent development,preparation process research, cementitious material properties, mechanical properties, durability and engineering applications. progress made and trends.On this basis, expounded the problem of large-scale widely used the geopolymers need to continue to address, and pointed out the direction for its further research and application.

Life Cycle Cost Analysis and the Decision of Concrete Durability Technology in the Coastal Regions: Evidence from China

2011 ◽  
Vol 243-249 ◽  
pp. 6389-6393
Author(s):  
Feng Xing ◽  
Xu Ming Mi
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Influence Factors ◽  
The United States ◽  
Life Cycle Cost Analysis ◽  
Concrete Durability ◽  
Analysis Model ◽  
Labor Costs ◽  
Advanced Technologies ◽  
Selection Of

This paper carries on the analysis from the perspective of the life cycle cost of coastal concrete structures’ durability. On the first place, this paper defines the scope and stages of life cycle of concrete durability. Second, the paper studies the influence factors of life cycle cost, and constructs an analysis model. Finally, it constructs and analyzes five solutions of concrete durability of the Shenzhen expressway project. The analysis results reveal that the life cycle cost about coastal concrete is a complex and dynamic system, which may influenced by many factors. The change of each factor will inevitably affect the selection of technology. At the same time, compared with the United States, maintenance-related labor costs and the price of concrete is much lower in China, so the results from the analysis, it seems that the advanced technologies related to the durability are not the more economic solution currently. However, if the changes about these factors are considered, the analysis results are different.

scholarly journals Evaluation of Pozzolanic Reactivity of Artificial Pozzolans

2012 ◽  
Vol 730-732 ◽  
pp. 433-438 ◽  
Author(s):  
Jorge Pontes ◽  
António Santos Silva ◽  
Paulina Faria
Keyword(s):  
Calcium Hydroxide ◽  
Building Materials ◽  
Activity Index ◽  
Test Methods ◽  
Concrete Durability ◽  
Interesting Issue ◽  
Pozzolanic Reactivity ◽  
Different Types ◽  
Pozzolanic Materials ◽  
Selection Of

Pozzolanicity is a very interesting issue regarding building materials, as a way to enhance mortars and concrete durability. This property results from the reaction between calcium hydroxide and silica and alumina based materials. Different types of natural and artificial pozzolans show pozzolanic activities that differ depending on the materials characteristics. Therefore, the study of this property, namely its reactivity with calcium hydroxide, reveals itself to be important in the selection of the type and content of these materials. This paper presents the results of several pozzolanic reactivity methods, applied to different pozzolanic materials. The selected pozzolanic methods include Chapelle method, Fratinni method and Strength Activity Index. Those tests have been applied to evaluate the reactivity of various kinds of artificial pozzolans. The correlation between the test methods are presented and discussed.

Research on the Solutions to the Concrete Durability of Newly-Built Tunnel Structure

2011 ◽  
Vol 243-249 ◽  
pp. 3663-3669
Author(s):  
Hai Yan Wang ◽  
Wen Ge Qiu ◽  
Xue Feng Chen ◽  
Hao Gu
Keyword(s):  
New Technology ◽  
Cementitious Materials ◽  
Poor Quality ◽  
Concrete Durability ◽  
Water Usage ◽  
Small Water ◽  
Geological Conditions ◽  
Road Tunnels ◽  
Initial Support ◽  
Secondary Lining

Through the survey about the durability of existing railway and road tunnels, it is found that there are different kinds of defects in most tunnels concerning poor durability. This phenomenon exists for a number of reasons among which the main ones are geological conditions , hydrological conditions, types of concrete structures, poor grading, larger second lining thickness, excessive larger stiffness and the poor quality construction. Solutions of these problems are provided in this paper. Specific measures are using multiple composite cementitious materials (the cocktailtreatment), providing composite cementitious materials with mixing station mode, using effective superplasticizer with low water-cement ratio and small water usage, adding appropriate amount of cellulose fibers in concrete, emphasizing the initial support and belittling the secondary lining, using reasonable maintaining technology, using new technology of Waterproof Plate. These measures may serve as reference for tunnels’ design and construction.

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