The mix design of a self-compacting concrete SCC is a complex operation that requires finding a good combination of compatible materials, and the proper dosage of each of these components in order to obtain a formulation that meets the properties of SCC fluidity and homogeneity. Multiple approaches have been developed in the world wide for the formulation of a self-compacting concrete. Most methods of formulation are currently designed empirically. These methods are mainly based on the fact that the BAP is a two-phase material.
|Published (Last):||4 April 2017|
|PDF File Size:||4.48 Mb|
|ePub File Size:||13.13 Mb|
|Price:||Free* [*Free Regsitration Required]|
The user has requested enhancement of the downloaded file. Yousfi1, L. Nouri1, M. Received: 15 December ; Accepted: 10 April of ABSTRACT Following a comparative study of a number of representative methods for the preparation of a concrete mix, the present paper presents the results one of such methods, namely that of ve Dreux-Gorisse. This method combines a graphical approach with an analytical one, alongside the use of established correction tables. This study therefore proposes to present the various stages necessary for preparation of a concrete mix using the Dreux-Gorisse method in an automatic way.
The purpose of this automation is to enable the preparation of a i variety of mixes, taking into account the presence of several parameters. This approach ch allows obtaining mixes in a comprehensive manner, which eventually can lead to a comparison with other methods for the preparation of concrete mixes. Ar Keywords: Concrete mix; dreux-gorisse; automation; strength; deformability; workability.
But almost one and a half century ago, a new era started with the invention of concrete. Since, this material became the object of numerous studies, always with the intention of improving its strength, ductility, workability and economy.
Saidani www. Yousfi, L. Nouri, M. Saidani and H. Hadjab or even steel. In what follows, definitions of some of the main properties of this material are given, according to different authors, e.
There are a number of definitions, but they to join each other. Concrete is a mixture of very different constituents: liquid water , active powder sociable and solid inert aggregates: big wholesale trade sands down: gravels or crushed stones. This mixture is dosed in order to acquire at the time of the implementation a proper consistency, and after hardening requested qualities, according to which the desired concrete composition is obtained .
D As there are several methods of concrete mixing, the authors attempted to cover the most popular ones with the aim of broadening the investigation. Methods initially covered include SI those reported in references . The authors made the decision to only concentrate on the method of Dreux-Gorisse, as it was found to be the most user friendly.
The study of the composition of a concrete mix consists in defining the optimum mixture of the aggregates as well as the proportions in cement and water, and this with the intention of accomplishing the desired concrete qualities.
The chosen Dreux-Gorisse composition methods lead to volumic ve or weighted contents of binders and granulates. In the present work, the weighted contents have been used. The passage from one content to another may be carried out by the knowledge of apparent density granulates used in bulk. Both Ar cases present advantages and disadvantages and depend on the size of the granulates which constitute the composition.
So, the continuous granularity allows acquiring more plastic concretes with a good workability. Conversely, the discontinuous granularity gives concretes with a maximum of large size granulates gravels and a minimum of small size granulates sand , leading in general to a better compressive strength in respect to the continuous granularity but this result is reached to the detriment of the workability that is one of the two main concrete qualities.
The concrete composition methods, in their diversities, are only approaching the true compositions, since these are always corrected in situ. Every method for obtaining a concrete mix has its hypotheses, its advantages and its disadvantages.
In the present study, the authors developed algorithms and a computer program with the intention of arriving at the required optimum concrete mix as quickly as possible. These programs also allow the possibility of a multitude of formulations in an automated and a rather short period of time. The choice in presenting the data and results in a table form greatly simplifies the operator task.
If one or several characteristics of a concrete mix are changed eg. The authors worked out the programming of several methods, but the most arduous proved to be that of Dreux-Gorisse, because it calls upon other programs, among others, that of the particle size curve of reference.
It would be necessary to know if structure is massive or high, if it is thin or thick, or if it is heavily reinforced or not.
The position of the reinforcement in the most reinforced zones must be known as well. The consistency depends on the structure type, the concreting difficulty and on the clamping means as it is shown in Table 1.
Ar Table 1: Relationship between consistency, concrete clamping, Abrams cone collapse and number of impacts of the C. S test. Hadjab 2. This latter will be adjusted subsequently through plasticity and workability tests. Aggregates 2. Sand must also be clean, its required fineness modulus value must range from 2.
Proposed distribution curves for concrete sands granularity . Granular reference curve and aggregates content On a granulometric analysis graph, a reference composition AOB is drawn. Then, the dividing lines between each aggregates type are drawn. Consequently, the percentage in net volume of each of the aggregates g1, g2, g3 etc Compactness Coefficient Ar The compactness coefficient is calculated as the absolute volumes of the solid materials VM divided by the total volume of implemented fresh concrete i.
As the concrete composition methods are widely dependent on empirical results, their programming is often reduced to predefined tables taking into account implementation parameters. It seems wise to avoid a sequential treatment, which would be only weighting down the www.
Hadjab program analysis without bringing any real effective benefit, to the advantage of a pseudo- parallel treatment in a worksheet form where data and results are gathered in a same simpler and more intuitive table to be exploited than a values list even structured. This Dreux-Gorisse method is not easy to program because it requires a prior treatment from the granulometric curves of the concrete different components.
This prior treatment consists in preparing the characteristic points which are necessary for the determination of the reference curve. The method combines a graphical and an analytical treatment associated with a consultation of correction table.
Figures 3 to 4 form a series of flowcharts that must be treated in parallel. Flowchart for the determination of the reference granulometric curve parameters. Dreux-Gorisse method flowchart www. Hadjab 4. To make the program working, the granulometric curve worksheet must be fully and correctly completed. It must be checked that the aggregates and cement apparent and real densities have been D indicated.
Ar www. Indeed, in order to obtain the requested mixture, it is sufficient to mention the required characteristics such as: fineness modulus, consistency, strength, etc. This method allows achieving a great number of concrete mixtures, thus leading to a global insight of their variation.
Moreover, the acquired programming results can be used as concrete mix design charts. In the present work, the cement Portland artificial Nevertheless, other cements or cement classes can be used as data with no difficulties.
D One of the aims of the present study is to simplify the task of those who are interested in concrete formulations according to Dreux-Gorisse method. Finally, it is hoped that the proposed automatization will allow a saving in the time taken SI in the determination of the concrete mixture. Venuat M. Faury J. Sa Confection et son Transport sur les Chantiers. Vallette R. Joisel A. R, Juin Dreux G. Dreux G, Festa J. Neville AM. Baron J, Olivier JP. Auchatraire A.
I, France, Related Papers. By Mohamed Benmalek. Concrete mix design containing calcareous tuffs as a partial sand substitution. By Kamel Silhadi. By Luc Courard. Mix proportioning and performance of a crushed limestone sand-concrete.