Description:FIELD OF THE INVENTION
The present invention relates to methods of evaluating the flow properties and workability of Self-Compacting Concrete (SCC). More specifically, the invention provides a modified fill-box test for measuring both the filling and passing ability of SCC in its fresh state. This method aims to provide more accurate and reliable results, particularly when steel rods in multiple directions are used to form obstacles in the test.
BACKGROUND OF THE INVENTION
The important requirements of Self-compacting concrete are tested in its fresh state. The main requirements are:
1) Filling ability
2) Passing ability
3) Segregation resistance
The filling ability of SCC is evaluated by Slump flow test, T50cm slump flow, Orimet and V-funnel tests. The passing ability of SCC is evaluated by L-box test, J-ring test, U-box test and Fill-box test. The segregation resistance of SCC is evaluated by V-funnel test atT5 minutes and GTM screen stability test. Among all the tests, fill-box test may be selected for measuring the filling and also passing ability of SCC. The remaining tests are either testing passing ability of filling ability. Hence more than two more tests are to be conducted for predicting the performance of fresh SCC. The fill-box test is the only acceptable method to evaluate both passing and filling ability of SCC. However, the main drawback of fill-box test is to prepare 42 liter of SCC for testing. The filling percentage is measured at the end of the test after passing the SCC through the 35 obstacles of 20 mm PVC pipes within 8 seconds. All the rods used to form the obstacles in the box are in single direction only. Meantime, variations in results are noticed.
In order to avoid these drawbacks, a modified fill-box test was developed with the capacity of 5.3 liter (equal to slump cone volume) with steel rods of various diameters depends upon the practical cases. The obstacle steel rods are placed in both the direction to get the exact flow and passing performance of SCC. The transparent cylinder box is having an opening at top and also a horizontal shutter. A slump cone is placed in an inverted manner and fills the fresh SCC within one minute and allows the fresh concrete to fill the cylindrical box after opening the shutter. The time taken to completely fill the 5.3 liter concrete in the modified box is the scale of measurement to evaluate the filling and passing ability of fresh SCC.
Self-Compacting Concrete (SCC) is a highly flowable, non-segregating concrete that can spread and fill formwork under its own weight without the need for mechanical vibration. The increasing use of SCC in construction projects, especially in complex structural elements with dense reinforcement, has led to the need for accurate and reliable testing methods to evaluate the fresh state properties of SCC, including its filling ability, passing ability, and segregation resistance.
Several traditional tests have been used to assess these properties, including the slump flow test, T50cm slump flow, Orimet test, V-funnel test, L-box test, and others. Among these, the fill-box test is commonly used to evaluate both the filling and passing abilities of SCC. However, the conventional fill-box test presents significant drawbacks, such as requiring large quantities of concrete (42 liters) and being prone to variations in results. In the traditional fill-box method, SCC is passed through obstacles created by steel rods arranged in a single direction, which may not accurately represent real-world conditions, especially in areas with dense reinforcement like beam-column joints.
Moreover, the test is time-consuming and inefficient, and the results can be inconsistent due to the design of the obstacles, which only account for one direction of reinforcement. These limitations lead to inaccurate predictions of SCC performance in practical applications.
To address these issues, the present invention proposes a modified fill-box test with a smaller capacity (5.3 liters) and the addition of steel rods arranged in both horizontal and vertical directions. This design more accurately simulates real-world conditions where reinforcement is present in multiple directions, providing more reliable results for filling and passing ability evaluation of SCC. The modified test eliminates many of the drawbacks associated with the traditional method, offering a faster, more efficient, and precise testing approach for SCC performance in construction.
SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention.
This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.
Self-Compacting Concrete (SCC) is a highly flowable, non-segregating concrete that can spread and fill formwork under its own weight without the need for mechanical vibration. However, to evaluate its workability in the fresh state, certain critical properties must be assessed, including filling ability, passing ability, and segregation resistance.
While traditional tests such as slump flow and the fill-box test provide insights into SCC performance, the fill-box test suffers from certain limitations. Specifically, the conventional fill-box test requires 42 liters of SCC, and the results can be inaccurate when obstacles are arranged in a single direction. The new method proposed in this invention overcomes these issues by utilizing a modified fill-box with a 5.3-liter capacity, which incorporates steel rods placed in both horizontal and vertical directions to simulate more realistic scenarios, particularly in dense reinforcement conditions. This modified test allows for more accurate measurement of the flow and passing ability of SCC, reducing error and ensuring more reliable data.
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
The illustrated embodiments of the subject matter will be understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
FIGURE 1: A modified fill-box apparatus
The figure illustrates a modified fill-box apparatus designed for testing the flowability and passing ability of self-compacting concrete (SCC). It consists of the following components:
Inverted Slump Cone: A truncated cone with a 10 cm opening at the top. This cone is placed on top of the cylinder box.
20 cm Cover: A circular plate with a 10 cm hole in the center, placed on top of the inverted slump cone.
12 mm Diameter Rods: These rods are arranged in a grid pattern inside the cylinder box to create obstacles for the concrete to pass through.
20 cm Diameter Transparent Cylinder Box: This box serves as the main container for the test.
The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The modified fill-box test is designed to assess the filling and passing ability of SCC more accurately and efficiently. The new fill-box is smaller, with a total volume of 5.3 liters, which corresponds to the volume of a typical slump cone. The box is made of transparent material for easy observation of the concrete flow. It also features an opening at the top and a horizontal shutter to facilitate the controlled release of SCC. The figure 1 depicts a novel method for testing the fresh SCC to determine its filling and passing ability. It aims to address the limitations of existing methods like the slump flow test and the traditional fill-box test. The modified fill-box design uses a grid of rods in both directions, making it more suitable for testing SCC with steel reinforcement in both directions.
In the first stage, the SCC is prepared and evaluated for slump flow using standard slump flow tests. This helps assess its basic filling ability. The next step involves using the modified fill-box to evaluate both the filling and passing ability of the SCC. The fresh concrete is poured into the modified fill-box through a slump cone, placed in an inverted position, and allowed to fill the box within one minute after the shutter is opened. The time taken for the SCC to completely fill the box is used as a measure of both its filling and passing ability.
The box is equipped with steel rods arranged in both horizontal and vertical directions to simulate obstacles such as those found in reinforced concrete structures (e.g., beam-column joints). These rods are used to evaluate the passing ability of SCC as the concrete flows through the obstacles. The filling percentage is recorded after the concrete passes through these obstacles, which gives a more accurate picture of its performance in real-world scenarios.
, Claims:1. A method for testing the filling and passing ability of Self-Compacting Concrete (SCC), comprising:
Using a modified fill-box with a volume of 5.3 litres;
Providing steel rods in both horizontal and vertical directions to simulate obstacles;
Pouring fresh SCC into the modified fill-box through a slump cone;
Allowing the SCC to fill the box within one minute after opening a shutter;
Measuring the time taken to completely fill the box to evaluate the filling and passing ability of SCC.
2. The method as claimed in claim 1, wherein the steel rods are arranged in both directions to simulate reinforcement in concrete structures.
3. The method as claimed in claim 1, wherein the fill-box is made of a transparent material to allow visual observation of SCC behaviour during the test.
4. The method as claimed in claim 1, wherein the filling percentage of SCC is calculated after it passes through the obstacles within the test box.
5. The method as claimed in claim 1, wherein the time taken to fill the 5.3-liter box is used as a measure of the filling and passing ability of SCC.
6. A modified fill-box apparatus for testing the filling and passing ability of SCC, comprising:
A box with a volume of 5.3 litters;
Steel rods arranged in both horizontal and vertical directions within the box to simulate obstacles;
A slump cone for filling SCC into the box;
A horizontal shutter for releasing SCC into the box.
7. The apparatus as claimed in claim 6, wherein the box is made of a transparent material for visual observation during testing.
8. The apparatus as claimed in claim 6, wherein the steel rods are adjustable to simulate different reinforcement configurations.
9. The apparatus as claimed in claim 6, wherein the apparatus is designed for easy cleaning and maintenance after each test.
10. A system for evaluating the performance of Self-Compacting Concrete (SCC), comprising: A modified fill-box; Sensors for measuring the time taken to fill the box; A computer or control system for recording and analysing test results.