Name: aggregate size testing with sieve grading
Uploaded: 2024-11-07T14:48:25.000Z
Duration: 1 min 19 s
Channel: JoVE

L'analisi al setaccio degli aggregati viene eseguita utilizzando una serie di setacci impilati in ordine decrescente della loro dimensione di apertura dall'alto verso il basso.
 Le dimensioni dei setacci variano per gli aggregati grossolani e gli aggregati fini.
Un campione di aggregati essiccati all'aria viene pesato e setacciato attraverso i setacci, agitandoli meccanicamente o manualmente per un tempo specificato.
Nel processo, ogni setaccio trattiene le particelle più grossolane della sua dimensione di maglia, consentendo al contempo alle particelle più fini di passare al setaccio successivo.
Viene registrato il peso delle frazioni trattenute su ciascun setaccio, espresso in percentuale della massa totale e rappresentato in una tabella.
Partendo dal setaccio più fine e salendo verso l'alto, la percentuale cumulativa che passa attraverso ciascun setaccio viene calcolata e arrotondata all'uno percento più vicino.
Inoltre, un grafico semi-logaritmico viene utilizzato per rappresentare la percentuale di passaggio sull'asse y e le aperture del setaccio sull'asse x in scala logaritmica.
Su questo grafico, la percentuale di passaggio cumulativa corrispondente a ciascuna dimensione del setaccio è tracciata per ottenere la curva di classificazione, che indica la distribuzione delle particelle aggregate in base alle loro dimensioni.

analisi del setaccio e curve di classificazione

L'analisi del setaccio è un metodo utilizzato per determinare la distribuzione granulometrica dei materiali aggregati. Questo processo comporta i seguenti passaggi:
<ol style="padding-left: 35px; margin: 0;">
	<li>Viene pesata la quantità richiesta di campione essiccato di aggregato.</li>
	<li>Gli aggregati pesati vengono setacciati attraverso una serie di setacci con aperture delle maglie disposte in ordine decrescente, con il setaccio la maglia più grande in alto (colonna 1 della tabella 1).</li>
	<li>La pila di setacci viene scossa o fatta vibrare per facilitare la selezione delle particelle in base alle dimensioni.</li>
	<li>Dopo aver setacciato per un periodo di tempo specifico, il materiale trattenuto su ciascun setaccio viene pesato (colonna 2 della tabella 1).</li>
	<li>
		Il peso delle particelle trattenute su ciascun setaccio è espresso come percentuale della massa totale del campione (colonna 3 della tabella 1).
		<img alt="Equation1" src="/files/ftp_upload/16871/16871%20_Equation_PT_001v2.svg" style="height: 46px;">
	</li>
	<li>La percentuale cumulativa che passa attraverso ciascun setaccio viene calcolata arrotondata all'uno percento più vicino, a partire dal setaccio più fine e procedendo verso l'alto (colonna 4 della tabella 1).</li>
	<li>La curva di classificazione è tracciata su un grafico (Figura 1) in cui i valori delle ordinate rappresentano la percentuale di passaggio (Colonna 4 della Tabella 1) e i valori delle ascisse mostrano le aperture del setaccio (Colonna 1 della Tabella 1), impostate su una scala logaritmica.</li>
</ol>

Tabella 1: Dati per l'analisi del setaccio sulla sabbia

<table style="margin: 0 auto;">
	<tbody style="border: 1px solid black;">
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">Colonna 1</td>
			<td style="color: black; border: 1px solid black; text-align: center;">Colonna 2</td>
			<td style="color: black; border: 1px solid black; text-align: center;">Colonna 3</td>
			<td style="color: black; border: 1px solid black; text-align: center;">Colonna 4</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN (Apertura maglie)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">Peso trattenuto su ogni setaccio (g)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">Percentuale di peso trattenuto su ogni setaccio (%)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">Percentuale cumulativa che passa ogni setaccio (%)</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">(9,5 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">0</td>
			<td style="color: black; border: 1px solid black; text-align: center;">0</td>
			<td style="color: black; border: 1px solid black; text-align: center;">98+2 = 100</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN(4,75 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">10</td>
			<td style="color: black; border: 1px solid black; text-align: center;">2</td>
			<td style="color: black; border: 1px solid black; text-align: center;">88+10 = 98</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN(2,36 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">50</td>
			<td style="color: black; border: 1px solid black; text-align: center;">10</td>
			<td style="color: black; border: 1px solid black; text-align: center;">79+9 = 88</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN(1,18 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">45</td>
			<td style="color: black; border: 1px solid black; text-align: center;">9</td>
			<td style="color: black; border: 1px solid black; text-align: center;">61+18 = 79</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN(0,6 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">90</td>
			<td style="color: black; border: 1px solid black; text-align: center;">18</td>
			<td style="color: black; border: 1px solid black; text-align: center;">29+32 = 61</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN(0,3 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">160</td>
			<td style="color: black; border: 1px solid black; text-align: center;">32</td>
			<td style="color: black; border: 1px solid black; text-align: center;">10+19 = 29</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">UNI EN(0,15 mm)</td>
			<td style="color: black; border: 1px solid black; text-align: center;">95</td>
			<td style="color: black; border: 1px solid black; text-align: center;">19</td>
			<td style="color: black; border: 1px solid black; text-align: center;">10</td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;">Fondo della padella</td>
			<td style="color: black; border: 1px solid black; text-align: center;">50</td>
			<td style="color: black; border: 1px solid black; text-align: center;">10</td>
			<td style="color: black; border: 1px solid black; text-align: center;"></td>
		</tr>
		<tr>
			<td style="color: black; border: 1px solid black; text-align: center;" colspan="2">Peso totale dell'aggregato = 500 g</td>
			<td style="color: black; border: 1px solid black; text-align: center;" colspan="2"></td>
		</tr>
	</tbody>
</table>

<img alt="Figure1" src="/files/ftp_upload/16871/16871_Figure_PT_001.jpg">
Le curve di classificazione semplificano visivamente la distribuzione delle dimensioni delle particelle e sono essenziali per garantire che gli aggregati soddisfino le specifiche di classificazione richieste per i progetti di costruzione.

Analisi del setaccio e curve di classificazione

L'analisi al setaccio degli aggregati viene eseguita utilizzando una serie di setacci impilati in ordine decrescente della loro dimensione di apertura dall'alto verso il basso.
Le dimensioni ...

Education

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Aggregates and Water

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aggregate size testing with sieve grading

Aggregate size testing with sieve grading measures the particle size distribution of aggregate materials. It starts with a dried sample of aggregate that is weighed first. The sample is then sorted through a stack of square-opening sieves arranged from largest opening on top to smallest opening below.

The sieve stack is shaken or vibrated so the particles move through the openings by size. After a set time, the material left on each sieve is weighed. That weight is then written as a percentage of the total sample mass.

Next, the cumulative percentage passing each sieve is calculated to the nearest one percent. This value is found from the finest sieve and then moved upward through the stack. The data can be recorded for sieves such as ⅜ inch, No. 4, No. 8, No. 16, No. 30, No. 50, No. 100, and the bottom pan.

The grading curve is plotted on a graph using percentage passing on the vertical axis. The sieve aperture size is shown on the horizontal axis and uses a logarithmic scale. This curve gives a clear picture of particle size distribution and helps check whether aggregates meet grading requirements for construction projects.

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Aggregate Size Testing with Sieve Grading

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