Concrete Brick Making Machinein Iro

Regardless of the type, concrete block production revolves around four core steps: "Raw Materials → Mixing → Forming → Curing." Detailed control directly determines product quality:
1. Raw Material Mix Design (Determines Strength and Formability)
The core principle is "strength compliance + cost optimization." Typical mix ratios (by mass) are as follows:
Ordinary solid blocks (MU5): Cement (PO 42.5): Medium sand: Crushed stone (5-10mm): Water = 1:3.5:4.5:0.4 (a water-cement ratio of 0.4 ensures a dry, hard mix with a slump of 10-30mm).
Hollow blocks (MU3.5): 15%-25% fly ash may be added (to replace some cement). The mix ratio is adjusted to: Cement: Fly ash: Sand: Stone: Water = 1:0.5:3:4: 0.42 (improves workability and reduces costs);
Key requirements: Aggregate mud content ≤ 3% (otherwise, strength is affected); Cement initial setting time ≥ 45 minutes (to avoid rapid solidification after mixing).
2. Mixing and Distribution (to prevent aggregate separation)
Mixing Equipment: A forced mixer must be used (free-fall mixers are prohibited, as they can easily cause separation of sand and cement). The mixing time should be controlled within 120-180 seconds (starting from the moment all materials are added, and visually inspect the mixture to ensure there are no cement clumps and a uniform color).
Distribution Method: Hollow blocks require a "layered distribution device" (first apply the bottom layer, then insert a core puller, and finally apply the top layer) to avoid aggregate accumulation around the holes. Solid blocks can use a "whole-piece distribution" method, but the material content within the mold must be uniform (deviation ≤ 5%). 3. Pressing (Core Process, Determines Density)
Equipment: Fully automatic hydraulic brick making machine (pressure range 10-25 MPa). Different blocks require different pressures:
Solid load-bearing blocks: Molding pressure ≥ 18 MPa (density ≥ 1800 kg/m³);
Hollow non-load-bearing blocks: Molding pressure 12-15 MPa (to prevent cracking);
Permeable bricks: Molding pressure 8-10 MPa (to maintain porosity and ensure permeability).
Pressing process: "Slow pressing (speed 5-8 mm/s) → Holding pressure (3-5 seconds) → Rapid retraction." Low-frequency vibration (50-60 Hz, amplitude 0.3-0.5 mm) can be used during the holding stage to help fully compact the mixture. 4. Curing (Improving Strength and Preventing Cracking)
Curing is key to compensating for insufficient strength after molding. There are two main methods:
Steam Curing (for large-scale production):
Stationary: After molding, place the mold in a 20-25°C environment for 2-3 hours (to allow the cement to initially set);
Heating: ≤20°C/hour (to avoid cracking caused by excessive temperature differences) to 60-65°C;
Constant Temperature: Maintain for 6-8 hours (strength reaches at least 70% of the design value);
Cooling: ≤25°C/hour (to room temperature) before removing from the curing room;
Natural Curing (for small-batch production):
After molding, cover with geotextile or plastic film and water 3-4 times daily (to keep the surface moist). Cure for 7-14 days. (Avoid direct sunlight and wind during the curing period. Cover with insulation in winter.)