Name: fineness modulus from sieve analysis
Uploaded: 2024-11-07T14:48:25.000Z
Duration: 1 min 19 s
Channel: JoVE

Considérons un échantillon d’agrégats fins tamisés à travers un ensemble standard de tamis. Notez le poids des agrégats retenus sur chaque tamis.
Calculer le poids cumulé des agrégats conservés sur chaque tamis et l’exprimer en pourcentage du poids total de l’échantillon.
Si, par exemple, toutes les particules sont retenues sur ou au-dessus d’un tamis particulier, et que rien ne le traverse, le pourcentage cumulé retenu pour ce tamis et ceux empilés en dessous est de 100.
Le module de finesse est calculé en additionnant le pourcentage cumulé retenu sur chaque tamis et en divisant le total par 100.
Le module de finesse est un indice numérique qui représente le classement des granulats.
Lorsque l’on utilise des granulats provenant de la même source, de légères variations dans la gradation des granulats fins sont moins évidentes visuellement qu’avec des granulats grossiers.
Ces différences se refléteront dans la valeur du module de finesse, ce qui sera plus perspicace pour les agrégats fins que pour les agrégats grossiers.
En règle générale, la valeur du module de finesse pour les granulats fins varie de 2,3 à 3,1 ; plus la valeur est élevée, plus les agrégats sont grossiers.

module de finesse

Le module de finesse (FM) des granulats est un indice numérique qui mesure la grosseur ou la finesse des particules. Il est calculé en additionnant les pourcentages cumulés de granulats retenus sur chacun des tamis d'une série spécifiée et en divisant la somme par 100.
 Envisagez d'effectuer une analyse par tamisage sur du sable à l'aide d'un ensemble de tamis ASTM. Le poids des granulats retenus dans chaque tamis et dans le bac placé au fond est enregistré, comme indiqué dans la colonne B du tableau 1.
 Pour déterminer le module de finesse du sable, il faut calculer le poids cumulé des granulats retenus sur chaque tamis (colonne C du tableau 1) et l'exprimer en pourcentage du poids total (colonne D du tableau 1). Enfin, la somme des pourcentages cumulés des granulats retenus sur chaque tamis est déterminée et multipliée par 100 pour obtenir le module de finesse du sable.
 Tableau 1 : Analyse par tamisage sur sable
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
 <tbody>
 <tr>
 <td style="text-align: center;">Colonne A</td>
 <td style="text-align: center;">Colonne B</td>
 <td style="text-align: center;">Colonne C</td>
 <td style="text-align: center;">Colonne D</td>
 </tr>
 <tr>
 <td style="text-align: center;">Tamis ASTM</td>
 <td style="text-align: center;">Poids retenu sur chaque tamis (g)</td>
 <td style="text-align: center;">Poids cumulé retenu sur chaque tamis (g)</td>
 <td style="text-align: center;"> Pourcentage cumulé retenu sur chaque tamis (%)</td>
 </tr>
 <tr>
 <td style="text-align: center;">⅜ cm</td>
 <td style="text-align: center;">0</td>
 <td style="text-align: center;">0</td>
 <td style="text-align: center;">0</td>
 </tr>
 <tr>
 <td style="text-align: center;">N° 4</td>
 <td style="text-align: center;">5</td>
 <td style="text-align: center;">0+5 = 5</td>
 <td style="text-align: center;">5/500 = 1</td>
 </tr>
 <tr>
 <td style="text-align: center;">N° 8</td>
 <td style="text-align: center;">55</td>
 <td style="text-align: center;">5+55 = 60</td>
 <td style="text-align: center;">60/500 = 12</td>
 </tr>
 <tr>
 <td style="text-align: center;">N° 16</td>
 <td style="text-align: center;">65</td>
 <td style="text-align: center;">60+65 = 125</td>
 <td style="text-align: center;">125/500 = 25</td>
 </tr>
 <tr>
 <td style="text-align: center;">N° 30</td>
 <td style="text-align: center;">90</td>
 <td style="text-align: center;">125+90 = 215</td>
 <td style="text-align: center;">215/500 = 43</td>
 </tr>
 <tr>
 <td style="text-align: center;">N° 50</td>
 <td style="text-align: center;">160</td>
 <td style="text-align: center;">215+160 = 375</td>
 <td style="text-align: center;">375/500 = 75</td>
 </tr>
 <tr>
 <td style="text-align: center;">N° 100</td>
 <td style="text-align: center;">90</td>
 <td style="text-align: center;">375+90 = 465</td>
 <td style="text-align: center;">465/500 = 93</td>
 </tr>
 <tr>
 <td style="text-align: center;">Bac inférieur</td>
 <td style="text-align: center;">35</td>
 <td style="text-align: center;">Poids total = 465+35 = 500</td>
 <td style="text-align: center;">
 </td>
 </tr>
 </tbody>
</table>
<img alt="Equation1" src="/files/ftp_upload/16872/16872%20_Equation_PT_001v2.svg" style="height: 14px;">

<img alt="Equation2" src="/files/ftp_upload/16872/16872%20_Equation_PT_002v2.svg" style="height: 36px;">
 
En général, le sable a un module de finesse compris entre 2,3 et 3,1. Des valeurs plus faibles indiquent un sable plus fin, tandis que des valeurs plus élevées signifient que le sable est plus grossier.

Module de finesse

Considérons un échantillon d’agrégats fins tamisés à travers un ensemble standard de tamis. Notez le poids des agrégats retenus sur chaque tamis.
Calculez le ...

Education

Enseignement

JoVE Core

Civil Engineering

Génie civil

Unit 1

Unité 1

Aggregates and Water

Granulats et eau

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

Fineness Modulus

fineness modulus from sieve analysis

Fineness modulus is a numerical index used to describe how coarse or fine aggregate particles are. For sand, it is found from sieve analysis using a standard set of ASTM sieves. The result helps show whether the sample is finer or more coarse.

To calculate fineness modulus, first record the weight of aggregate retained on each sieve and in the pan at the bottom. Then find the cumulative weight retained on each sieve. Next, express each cumulative weight as a percentage of the total sample weight. The fineness modulus is obtained by adding those cumulative percentages and dividing the sum by 100.

A sand sample can be tested with sieves such as ⅜ inch, No. 4, No. 8, No. 16, No. 30, No. 50, and No. 100. In the example, the retained weights are 0 g, 5 g, 55 g, 65 g, 90 g, 160 g, 90 g, and 35 g in the bottom pan. The cumulative percentages retained are 0, 1, 12, 25, 43, 75, and 93, based on a total weight of 500 g.

In general, sand has a fineness modulus of about 2.3 to 3.1. Lower values mean the sand is finer. Higher values mean the sand is more coarse.

Fineness Modulus from Sieve Analysis

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Learn how fineness modulus is calculated from sieve analysis of sand, using cumulative retained percentages on ASTM sieves to judge particle size.

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JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

Fineness Modulus from Sieve Analysis

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