Prédiction des résistances du ciment au laitier durcissant sous une temperature variable

2001 ◽  
Vol 28 (4) ◽  
pp. 555-561 ◽  
Author(s):  
Bougara Abdelkader ◽  
Ezziane Karim ◽  
Kadri Abdelkader
Keyword(s):  
Construction Industry ◽  
Concrete Strength ◽  
Normal Concrete ◽  
Activation Temperature ◽  
Equivalent Time ◽  
Treatment Prediction ◽  
Different Temperatures ◽  
Curing Methods ◽  
Temperature Variable ◽  
Mineral Additives

The prediction of concrete strength has become a major concern that is forcing the construction industry to look closely at determining the appropriate time when to strip the form work or to apply prestress forces to new concrete. Normal concrete has different constitutions and can be subjected to different curing methods depending on the means available. Its characteristics are defined by the presence of mineral additives used to improve its efficiency. This has led us to establish a work plan to predict the strength of slag concrete, tested at different temperatures, from the data obtained from some control specimens of normal concrete, made only from clinker and subjected to a constant temperature of 20°C. The slag material was obtained from El-Hadjar (Algeria).Key words: slag, activation, temperature, finesse, thermal treatment, prediction, equivalent time, mortar, compression, cement, additives.

Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu
Keyword(s):  
Normal State ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Normal Concrete ◽  
Strength Criteria ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

The Impact of Heat Treatment on Pyrophyllite Structure and Acid-Soluble Properties

2011 ◽  
Vol 366 ◽  
pp. 326-329 ◽  
Author(s):  
Jun Jun Wu ◽  
Hai Feng Chen ◽  
Shi Jiang Zhao ◽  
Bin Li
Keyword(s):  
Heat Treatment ◽  
Thermal Activation ◽  
Acid Leaching ◽  
Basic Structure ◽  
Hydrochloric Acid Concentration ◽  
Activation Temperature ◽  
Different Temperatures ◽  
Ft Ir ◽  
Heat Activation ◽  
The Impact

This paper studied the influence of heat treatment on the pyrophyllite structure and acid-soluble properties of alumina. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by XRD, TG-DTA, FT-IR and quantitative analysis of Al2O3. The quantitative titration method studied the dissolve characteristics of the different heat treatment samples in different acid conditions, and then a numerical simulation was done. The results showed that at temperatures below 480 °C, the pyrophyllite did not change the basic structure. 480~700 °C dehydroxylation reaction occurred, and the structure water of pyrophyllite is removed, and then turned into partial pyrophyllite. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C, the dissolution amount of alumina was largest. These works could provide some theoretical basis for further application of pyrophyllite research.

scholarly journals Response of Recycled Brick Aggregate Concrete to High Temperatures

2019 ◽  
Vol 8 (10) ◽  
pp. 224-227
Keyword(s):  
Mechanical Properties ◽  
Air Pollution ◽  
Compressive Strength ◽  
Construction Industry ◽  
Fire Performance ◽  
Demolition Waste ◽  
Aggregate Concrete ◽  
Different Temperatures ◽  
Better Than ◽  
Made In

The abundant availability of demolition waste from construction industry is leading towards a significant problem of disposal, land and air pollution. The natural aggregate resources are also depleting due to development of construction activities. An attempt is made in this study to convert this waste into wealth by substituting the recycled brick from demolition waste to granite aggregate in production of the concrete. The granite aggregate (GA) is replaced with recycled brick aggregate (RBA) by 25% of its weight to produce M15 and M20 grades of concrete. The granite aggregate concrete (GAC) and recycled brick aggregate concrete (RBAC) were subjected to different temperatures between 100 to 1000oC for a duration of 3 hours and the mechanical properties such as compressive strength and flexural strength were examined to assess its fire performance. The response of RBAC is better than GAC at each temperature. The study revealed that the residual strength increases with the increase in grade of concrete at all temperatures.

scholarly journals Development of Activated Carbon Using One Step Carbonization and Activation Reaction by Polymer Blend Method

2015 ◽  
Vol 57 ◽  
pp. 156-162 ◽  
Author(s):  
S. Manocha ◽  
Parth Joshi ◽  
Amit Brahmbhatt ◽  
Amiya Banerjee ◽  
Snehasis Sahoo ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Surface Area ◽  
Surface Characteristics ◽  
Nitrogen Atmosphere ◽  
Activation Process ◽  
Average Pore ◽  
Activation Temperature ◽  
Optimum Synthesis ◽  
Different Temperatures ◽  
One Step

In the present work, a one step carbon activation process was developed by stabilized poly-blend. It is carbonized in nitrogen atmosphere and activated in steam in one step for known interval of times to enhance the surface area and develop interconnected porosity. The weight-loss behavior during steam activation of stabilized poly-blend at different temperatures, surface area and pore size distribution were studied to identify the optimum synthesis parameters. The results of surface characteristics were compared with those of activated carbon prepared by carbonization and activation in two steps. It was found that activation temperature has profound effect on surface characteristics. As activation temperature was raised from 800 °C to 1150 °C, surface area of activated carbon increased about three times. In addition to surface area, average pore diameter also increases with increasing activation temperature. Thus, activated carbon with high percentage of porosity and surface area can be developed by controlling the activation temperature during activation process.

scholarly journals Studi Kuat Tekan Beton Speedcrete Dengan Zat Additive Naphthalene Berdasarkan Variasi Umur

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Syifa Fauziah ◽  
Anisah Anisah ◽  
Sittati Musalamah
Keyword(s):  
Compressive Strength ◽  
Test Object ◽  
Treatment Process ◽  
Concrete Strength ◽  
Test Machine ◽  
Water Age ◽  
Normal Concrete ◽  
Compressive Strength Of Concrete ◽  
Normal Strength ◽  
Additive Materials

This research aims to determine the maximum compressive strength value of concrete speedcrete using naphthalene additive additive at each test age and compare with normal concrete 28 days. This research used cylindrical test object with diameter 15 cm and height 30 cm. Speedcrete concrete does not undergo the treatment process while the normal concrete test object through the treatment process. Testing compressive strength of concrete speedcrete using Crushing Test Machine tool. In this research the compressive strength was produced by using superplasticizer type naphthalene and compared with normal concrete without using additive. The target quality plan is fc '35 MPa with the use of additive dose of 1.7% of the weight of cement. The results of this research showed an increase in the value of compressive strength of concrete speedcrete with aadditive materials added naphthalene increased with increasing age of concrete. The results showed that the compressive strength of concrete speedcrete with naphthalene additive materials of 12 hours, 18 hours, 28 hours and 48 hours was 0.5 MPa, 17,81 MPa, 31,14 MPa and 45,77 MPa. Normal strength concrete strength with the addition of 20% water age 28 days that is equal to 54.76 MPa.

STRENGTH OF POROUS CONCRETE PAVEMENT AT DIFFERENT CURING METHODS

2015 ◽  
Vol 76 (14) ◽  
Author(s):  
Mohd Ibrahim Mohd Yusak ◽  
Ramadhansyah Putra Jaya ◽  
Mohd Rosli Hainin ◽  
Che Ros Ismail ◽  
Mohd Haziman Wan Ibrahim
Keyword(s):  
Concrete Strength ◽  
Concrete Pavement ◽  
Experimental Results ◽  
Conventional Concrete ◽  
Curing Conditions ◽  
Porous Concrete ◽  
Curing Methods ◽  
And Performance ◽  
Curing Method ◽  
Tensile Splitting Strength

Porous concrete pavement has been used in some countries as a solution to environmental problems. Contrary to conventional concrete pavement, there is still lack of knowledge in some areas of production and performance of porous concrete pavement. One of the issue concern is curing conditions. These greatly affect the performance of porous concrete pavement. This paper elaborates the experimental results examining the influence of curing method and makes a comparison between five different curing methods on the strength of porous concrete pavement specimens. The properties analyzed include compressive strength, tensile splitting strength and flexural strength. The experimental results indicate that the different curing methods give a different effect to concrete strength. Based on the results obtained in this experiment, curing method by using polyethylene bag promise a good result and better performance to porous concrete pavement specimen strength.

Variation of Concrete Strength with the Insertion of Carbon Nanotubes

2013 ◽  
Vol 818 ◽  
pp. 124-131
Author(s):  
Assed N. Haddad ◽  
Jorge F. de Morais ◽  
Ana Catarina J. Evangelista
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Construction Industry ◽  
Concrete Strength ◽  
Cement Composites ◽  
Deformation Properties ◽  
The Face ◽  
Non Destructive ◽  
Technological Community

Nanomaterials could change the face of modern construction because they are more resistant, more durable and have notable features. Concrete is a material widely used in construction industry worldwide. Carbon nanotube has been considered a new and outstanding material in nanoscience field with great potential application in the construction industry. The study presented in this paper, aims at assessing how carbon nanotubes can affect cement composites and so the concrete, in terms of microstructure and physical-mechanical properties. Three different ratios of carbon nanotubes have been searched: 0.20%, 0.40% and 0.60%. To evaluate the mechanical properties of the samples, destructive and non-destructive tests were carried out to obtain compressive strength, tensile strength by diametrical compression, dynamic modulus of elasticity as well as the determination of their deformation properties. This work also aims to motivate entrepreneurs and professionals in the sector of civil engineering on the advantages of the application of nanotechnology in construction, as well as providing information to the scientific and technological community in general.

Lateral Resistance Influencing Factor Analysis of Small Diameter Anti-Slide Pile Based on Orthogonal Test

2015 ◽  
Vol 777 ◽  
pp. 42-47
Author(s):  
Lian Liu ◽  
Mo Han Bai ◽  
Wen Long Lu
Keyword(s):  
Construction Industry ◽  
Influencing Factor ◽  
Concrete Strength ◽  
Small Diameter ◽  
Shear Resistance ◽  
Deep Foundation ◽  
Slope Stabilization ◽  
Lateral Resistance ◽  
Sensitive Factor ◽  
Reinforcement Bar

Following with the development of construction industry, small diameter anti-sliding pile has been widely implemented in slope stabilization and deep foundation support. Much attention has been paid on researching lateral resistance of pile body. By orthogonally testing factors of small diameter anti-slide reinforcement pile models including concrete strength, sectional dimension and reinforcement bar gauge, The article analyzed sensitive influence to lateral resistance of pile body. The results indicate that concrete strength appears the most sensitive factor, next sectional dimension, and then reinforcement bar gauge. By comparing with shearing test of small diameter anti-slide reinforcement pile models, the conclusion follows that reinforcement of pile body does not fully unleash its shear resistance characteristic. Thus conclusion provides reference for implementation and designing of small diameter anti-slide pile.

scholarly journals An Auto-Calibrating Semi-Adiabatic Calorimetric Methodology for Strength Prediction and Quality Control of Ordinary and Ultra-High-Performance Concretes

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 96
Author(s):  
Marco Viviani ◽  
Luca Lanzoni ◽  
Vincenzo Savino ◽  
Angelo Marcello Tarantino
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
Ultra High Performance Concrete ◽  
Structural Element ◽  
Construction Operations ◽  
Equivalent Time ◽  
Normal Strength ◽  
Good Agreement

A timely knowledge of concrete and ultra-high-performance concrete (UHPC) strength is possible through the so-called strength-equivalent time (Et) curves. A timely knowledge of concrete strength is useful, for instance, to precisely determine when the shores of a hardening structural element can be safely removed. At the present time, the preparation of the strength-Et curves requires time-consuming and labor-intensive testing prior to the beginning of construction operations. This paper proposes an innovative method to derive the strength-Et and total heat-Et curves for both normal strength and UHPC. Results confirmed that the proposed method is fast, inexpensive, self-calibrating, accurate and can detect any variation of the concrete mix proportions or components quality. In addition, the quality of predictions of strength–maturity curves can be constantly improved as the specimens’ population increases. Finally, results obtained with the proposed method were compared with those obtained using standard methods, showing a good agreement.

scholarly journals PREPARATION AND CHARACTERIZATION OF CARBON FROM THE FRUIT OF BRAZIL NUT TREE ACTIVATED BY PHYSICAL PROCESS

2019 ◽  
Vol 43 (2) ◽  
Author(s):  
Michelle Ferreira da Silva Rimoli ◽  
Roberta Martins Nogueira ◽  
Stela Regina Ferrarini ◽  
Pryscila Machado de Castro ◽  
Evaldo Martins Pires
Keyword(s):  
Activated Carbon ◽  
Raw Materials ◽  
Chemical Properties ◽  
Internal Surface ◽  
Physical Activation ◽  
Brazil Nut ◽  
Internal Surface Area ◽  
Activation Temperature ◽  
Different Temperatures ◽  
Physical And Chemical

ABSTRACT Activated carbon is the name of a big group of materials that presents high degree of porosity and, consequently, an extended internal surface area, with physical and chemical adsorption properties. Innumerous raw materials can be used as precursors, especially biomass. The objective of this study was to obtain activated carbon from physical activation of the fruit of Brazil nut tree (“ouriço”) and to evaluate its physical and chemical properties in function of the differences between the temperatures and atmospheres of activation. The samples were carbonized at 3 different temperatures and the carbons were activated under atmosphere saturated by CO2 or steam. The results showed the influence of activation temperature and atmosphere on physicochemical characteristics of carbon. The carbon from woody Brazil nut seed capsule activated by CO2 and steam at different temperatures had a microporous profile, indicating its use to adsorb organic molecules of small dimensions. Basic characteristic was observed on samples and the carbon produced was thermally stable. Best quality was attributed to carbon activated by steam at 800 °C.

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