Originating Common Defects in Hollow Bricks: Concrete Brick Machine Parameter Adjustment and Raw Material Ratio Optimization

Originating Common Defects in Hollow Bricks: Concrete Brick Machine Parameter Adjustment and Raw Material Ratio Optimization

Against the backdrop of rapid development in the construction industry, hollow bricks are widely used in various building walls due to their advantages such as lightweight, heat insulation, and sound insulation. However, common defects during production, such as dimensional deviations, cracks, and substandard porosity, directly affect the strength, durability, and construction efficiency of hollow bricks. This article systematically elaborates on the core strategies for eradicating hollow brick defects from two dimensions: adjusting concrete brick machine parameters and optimizing raw material ratios.

I. Root Cause Analysis of Common Defects and Two-Pronged Approach

Defects in production are usually the result of the combined effects of equipment operating conditions and the raw material system. For example:
Crack Defects:These may stem from insufficient vibration or uneven material distribution leading to a loose internal structure, or from insufficient cement content or poor aggregate gradation, resulting in insufficient slurry bonding strength and tensile strength.

Dimensional and Appearance Defects:Such as rough edges and chipped corners on the bricks, are often closely related to mold wear and unstable pressure of the press head (equipment parameters). They may also be affected by excessively dry or poorly fluid materials (raw material issues), leading to incomplete molding. Strength Defects: If compressive and flexural strengths fail to meet standards, it's necessary to simultaneously check whether the vibration frequency and compaction time are sufficient (to ensure density), and whether the proportion of cementitious materials, water-cement ratio, and aggregate strength are reasonable.

Therefore, addressing any defect requires coordinated diagnosis and intervention along two main lines: "equipment" and "raw materials."

II. Concrete Brick Machine Parameter Adjustment: Precise Control of the Production Process

1.Mold Maintenance and Replacement: The "First Line of Defense" Against Dimensional Deviations

The mold is the core component in hollow brick forming, and its wear directly affects the dimensional accuracy of the product. After long-term use, iron molds are prone to deformation due to friction and vibration, leading to problems such as brick dimensions exceeding standards and reduced porosity. Prevention Measures:

Regular Calibration: After producing 1.2 million to 1.5 million bricks, conduct dimensional checks on the mold to ensure that length, width, and height errors are controlled within industry standards.

Dynamic Replacement: Establish a mold life record. When wear causes a porosity decrease of more than 5% or a brick breakage rate exceeds 3%, replace the mold immediately.

2. Transportation Protection: When transferring molds from the production line to the curing yard, use shock-absorbing devices (such as rubber pads) to reduce the risk of collision and prevent edge damage.

 Load Adjustment: Optimize Molding Pressure and Cycle. The brick machine load adjustment should follow a stepped process of "no load → light load → medium load → full load," ensuring stable equipment operation through parameter optimization. Key steps:
Light load adjustment: Run at 30%-50% load rate, focusing on checking the uniformity of material distribution (gap between the bottom plate of the cylinder and the large disc ≤ 0.5mm) and molding pressure (press head pressure value should reach approximately 40% of the design value).

Medium load adjustment: At 60%-80% load rate, adjust the pressing head speed (recommended 0.5-1 second/cycle) and holding time (2-3 seconds) to ensure the brick blank is free of cracks and has intact edges and corners.

Full-load commissioning: Verify output (e.g., brick production per hour) and brick quality (compressive strength ≥ MU10) at 100% load rate, while monitoring motor temperature rise (≤70℃) and bearing wear.

3. Vibration and conveyor control: Reducing hidden damage. Excessive vibration or mismatched conveyor belt speed during production can easily lead to loose internal structure or surface scratches in the bricks. Optimization solutions:
Vibration frequency: Adjust the vibration table frequency according to raw material characteristics (e.g., sand and gravel particle size) (50-60Hz recommended) to avoid excessive vibration causing aggregate segregation.

Conveying synchronization: Match the molding speed with the conveyor belt speed (e.g., when producing 10 bricks per minute, set the conveyor belt speed to 0.5 m/s) to prevent brick accumulation or stretching deformation.

III. Scientific optimization principles of raw material ratio. High-quality raw materials and scientific ratios are the intrinsic foundation for producing high-quality hollow bricks.

1. Cementitious material system: Rationally determine the ratio of cement to admixtures (e.g., fly ash, slag powder). 1. **Enhancing Early Strength and Carbonation Performance:** While ensuring early strength and carbonization performance, fully utilize the morphological effects and activity of admixtures to improve workability, reduce costs, and minimize shrinkage.

2. **Aggregate Grading and Quality:** Aggregates (sand, stone chips, crushed stone, etc.) account for over 70% of the brick volume, making their gradation crucial. Good continuous gradation minimizes porosity and increases density and strength. Strictly control the maximum aggregate size (usually not exceeding 1/3 of the wall thickness), mud content, and impurities.

3. **Water-Cement Ratio and Admixtures:** Water-cement ratio is a core parameter affecting workability and final strength. While meeting the required workability for molding, minimize the water-cement ratio to achieve higher strength and durability. Excessive moisture is a major cause of shrinkage cracks and strength reduction.

Admixtures: Appropriate use of water-reducing agents can improve fluidity while reducing water consumption; plasticizers improve molding performance; and, when necessary, incorporate early-strength agents or fibers (such as polypropylene fibers) to enhance crack resistance.

Raw Material Homogenization: Establish a raw material pre-homogenization stockpile to ensure the stability of the composition of each batch of materials entering the production line. This is a prerequisite for achieving accurate proportioning and consistent quality.

IV. Long-Term Management: Key Points for Daily Maintenance of Raw Materials and Brick Machines To eradicate defects in hollow bricks, it is necessary not only to optimize the raw material proportions and brick machine parameters but also to establish a daily management mechanism to prevent the recurrence of defects and achieve large-scale, high-quality production.

1. Daily Raw Material Management: Establish an incoming raw material inspection system. Test each batch of raw materials for indicators such as mud content, particle size distribution, and cement strength. Unqualified raw materials are prohibited from entering the warehouse. Raw materials should be stored in classified and zoned areas to avoid mixing. Fine and coarse aggregates should be protected from rain and moisture to prevent clumping. During mixing, strictly adhere to the proportioning to ensure accurate metering (metering error ≤ ±2%), following the principle of "dry mixing first, then wet mixing" to ensure uniform mixing and avoid segregation of the mixture.

2. Daily Maintenance of the Brick Machine: After each day's production, clean the main machine cavity, molds, and mandrel of residual material; check the wear of the mandrel and molds, and replace worn parts promptly; lubricate key parts of the hydraulic and vibration systems, replenish lubricating oil, check hydraulic oil purity, and filter or replace it regularly; calibrate brick machine parameters (pressing pressure, vibration frequency, mandrel verticality) weekly, and conduct a comprehensive equipment overhaul monthly to ensure stable equipment operation; operators must undergo professional training and be familiar with equipment operating procedures to avoid defects caused by operational errors.

3. Quality Sampling Inspection Mechanism: Establish an hourly sampling inspection system, focusing on checking the appearance of the bricks, the regularity of the holes, and dimensional deviations; test the compressive strength of each batch; maintain production records, recording information such as raw material ratios, brick machine parameters, and curing time to facilitate traceability of quality issues and timely optimization and adjustments.

Conclusion:

The common defects in hollow bricks are not caused by a single factor, but are the result of the synergistic effect of multiple factors, including raw material ratios, brick machine parameters, operating procedures, and maintenance management. As a core piece of equipment in concrete brick production, the precision of the machine's parameters directly determines the quality of the finished product, while a scientific raw material ratio is fundamental to avoiding defects.

For brick factories, eliminating hollow brick defects doesn't require blindly upgrading equipment. Instead, they should prioritize optimizing raw material ratios and adjusting brick machine parameters. Combining this with the practical solutions provided in this article, they can specifically address various defects and improve product qualification rates. Simultaneously, establishing daily management and quality inspection mechanisms will achieve long-term optimization, reducing production costs and enhancing product competitiveness, thus meeting the high-quality development needs of the green building materials industry by 2026.