Fill Box Apparatus / SELF COMPACTING CONCRETE (SCC)

Advance Information*

Introduction

The Fill Box Apparatus, also referred to as "SELF COMPACTING CONCRETE (SCC)" by EIE 435, stands as a critical component in the scope of modern civil engineering and construction testing gear. Compliant with ASTM C1621 standards, the apparatus is engineered to evaluate the flowability and passing ability of Self-Consolidating Concrete (SCC). Selections of SCC are increasingly favored for their streamlined application in complex frameworks where traditional vibration techniques prove inefficient or impractical. With a robust design and precision measurement capabilities, the Fill Box Apparatus facilitates reliable assessments crucial for maintaining high construction quality.

Compliance With Standards

The Fill Box Apparatus by EIE 435 complies strictly with the ASTM C1621 standard. This standard outlines test methods for standardized evaluations of SCC's properties. The adherence to such an internationally recognized standard speaks volumes about the credibility and performance accuracy expected from this apparatus. ASTM, being a global leader in technical standards, ensures that the tests conducted are reliable, repeatable, and relevant across different applications and geographies.

Significance of ASTM C1621

The ASTM C1621 standard focuses primarily on the passing ability and flowability of SCC. Flowability addresses how easily the concrete can spread under its own weight, while passing ability evaluates the SCC's competency to navigate through the thickets of reinforcing bars and embedded materials. These parameters are essential for ensuring the concrete fills intricate molds and frameworks without voids or weaknesses, thus guaranteeing structural integrity.

Fill Box Technique

The Fill Box test, sometimes called the "Kajima test," is a specialized method designed to measure the filling ability of self-compacting concrete, especially when the maximum aggregate size is 20 mm. This test provides crucial insights, enabling engineers to examine the SCC's behavior in real-world scenarios where fluidity and obstacle navigation are imperative.

Design and Construction

The Fill Box Apparatus consists of a rectangular box, generally fabricated from robust metal to endure repetitive testing during the construction life cycle. The box is divided into several compartments by slotted partitions to simulate the presence of reinforcement bars. The structural configuration aims to replicate actual construction situations, making the test results highly applicable to practical scenarios.

Components of the Fill Box Apparatus

1. Fill Box: The primary testing component, generally constructed from stainless steel or another durable metal. The box dimensions are calibrated to ensure accurate testing of concrete flow.

2. Partitions: Adjustable slotted metal partitions within the box, meant to act as obstacles to evaluate the passing ability of the SCC.

3. Measuring Tools: Includes graduated scales or markers along the sides of the box to gauge the level of concrete pour and flow within the compartments.

4. Release Mechanism: Lever or pulley systems to facilitate the controlled release of concrete, simulating realistic flow conditions within the containment of the fill box.

Technical Specifications

• Material: High-grade stainless steel or equivalent durable metal
• Maximum Aggregate Size: 20 mm
• Compliant Standards: ASTM C1621
• Exterior Dimensions: Typically customized as per specific testing requirements but follows standard dimensions used in construction for ease of comparison.
• Slotted Partitions: Number and size are adjustable for simulating various reinforcement layouts.

Operational Mechanism

To conduct a Fill Box test, the following procedural steps are generally observed:

1. Preparation: Setting up the fill box apparatus with empty slots and ensuring all equipment is clean and calibrated.
2. Sample Preparation: Preparing a batch of SCC, ensuring it is thoroughly mixed and free of air pockets.
3. Pouring: Pouring the SCC into the box, either in a controlled release to assess slow flow conditions or in a more rapid release for high flow scenarios.
4. Observation: Monitoring the concrete as it flows through the partitions, noting any areas where flow is restricted or impeded.
5. Measurement: Using the graduated scales to measure the height of the concrete in different sections of the box, thereby assessing its capacity to fill the available space fully.
6. Analysis: Documenting the results and analyzing them against standard benchmarks provided by ASTM C1621.

Applications

The Fill Box Apparatus finds widespread application in the following areas:

• Construction Material Testing: Ensuring that batches of self-consolidating concrete meet the required standards before application in structural components.
• Quality Control: Serving as a routine quality control measure for contractors and builders to confirm the performance of SCC in varied conditions.
• Research and Development: Facilitating the development of new SCC formulas or admixtures by providing a reliable method for assessing performance improvements.
• Educational Laboratories: Providing a practical tool for civil engineering students and researchers to understand the properties and behavior of SCC in a controlled environment.

Benefits of the Fill Box Apparatus

1. Enhanced Quality Control