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

Рассмотрим образец мелких заполнителей, просеиваемых через стандартный набор сит. Обратите внимание на вес заполнителей, удерживаемых на каждом сите.
Рассчитайте совокупный вес заполнителей, удерживаемых на каждом сите, и выразите его в процентах от общего веса образца.
Если, например, все частицы удерживаются на определенном сите или над ним и через него ничего не проходит, то суммарный процент, сохраняемый для этого сита и частиц, уложенных под ним, принимается за 100.
Модуль тонкости помола рассчитывается путем суммирования накопленного процента, оставшегося на каждом сите, и деления общего на 100.
Модуль тонкости помола — это числовой показатель, представляющий сортировку заполнителей.
При использовании заполнителей из одного и того же источника небольшие вариации градации мелких заполнителей менее заметны визуально, чем при использовании крупных заполнителей.
Эти различия будут отражены в значении модуля крупности, которое будет более информативным для мелких заполнителей, чем для грубых.
Как правило, значение модуля крупности для мелких заполнителей колеблется от 2,3 до 3,1; чем выше значение, тем крупнее агрегаты.

Модуль тонкости

Модуль тонкости (FM), или дисперсности, заполнителя — это числовой индекс, который измеряет грубость или тонкость частиц. Он рассчитывается путем сложения совокупных процентов заполнителя, удерживаемых на каждом из указанных рядов сит, и деления суммы на 100.

Рассмотрим возможность проведения ситового анализа песка через набор сит ASTM. Вес заполнителя, удерживаемого в каждом сите и поддоне, помещенном на дно, регистрируется, как указано в столбце B Таблицы 1.

Чтобы определить модуль тонкости песка, вычислим совокупный вес заполнителя, удержанного на каждом сите (столбец C таблицы 1), и выразим его в процентах от общего веса (столбец D таблицы 1). Наконец, определим сумму совокупных процентов заполнителя, удержанного на каждом сите, и умножим на 100, чтобы получить модуль тонкости песка.

Таблица 1: Ситовой анализ песка

<table style="text-align: center;" border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Столбец A</td>
			<td>Столбец B</td>
			<td>Столбец C</td>
			<td>Столбец D</td>
		</tr>
		<tr>
			<td>Сито ASTM</td>
			<td>Вес, оставшийся на каждом сите (г)</td>
			<td>Суммарный вес, оставшийся на каждом сите (г)</td>
			<td>Совокупный процент, оставшийся на каждом сите (%)</td>
		</tr>
		<tr>
			<td>
			⅜ см
			</td>
			<td>0</td>
			<td>0</td>
			<td>0</td>
		</tr>
		<tr>
			<td>№ 4</td>
			<td>5</td>
			<td>0+5 = 5</td>
			<td>5/500 = 1</td>
		</tr>
		<tr>
			<td>№ 8</td>
			<td>55</td>
			<td>5+55 = 60</td>
			<td>60/500 = 12</td>
		</tr>
		<tr>
			<td>№ 16</td>
			<td>65</td>
			<td>60+65 = 125</td>
			<td>125/500 = 25</td>
		</tr>
		<tr>
			<td>№ 30</td>
			<td>90</td>
			<td>125+90 = 215</td>
			<td>215/500 = 43</td>
		</tr>
		<tr>
			<td>№ 50</td>
			<td>160</td>
			<td>215+160 = 375</td>
			<td>375/500 = 75</td>
		</tr>
		<tr>
			<td>№ 100</td>
			<td>90</td>
			<td>375+90 = 465</td>
			<td>465/500 = 93</td>
		</tr>
		<tr>
			<td>Нижний поддон</td>
			<td>35</td>
			<td>Общий вес = 465+35 = 500</td>
			<td></td>
		</tr>
	</tbody>
</table>
<img alt="Eq1" src="/files/ftp_upload/16872/16872%20_Equation_PT_001v2.svg" style="height: 14px;">
<img alt="Eq2" src="/files/ftp_upload/16872/16872%20_Equation_PT_002v2.svg" style="height: 36px;">
В целом, песок имеет модуль тонкости около 2,3–3,1. Более низкие значения указывают на более мелкий песок, а более высокие значения указывают на более крупный песок.

Рассмотрим образец мелких заполнителей, просеиваемых через стандартный набор сит. Обратите внимание на вес заполнителей, удерживаемых на каждом сите.
Рассчитайте...

Education

JoVE Core

Civil Engineering

Unit 1

Раздел 1

Aggregates and Water

Заполнители и вода

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

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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key terms and concepts

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

Fineness Modulus from Sieve Analysis | JoVE K12

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.

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Fineness Modulus from Sieve Analysis

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