The statement "How do you make concrete for bricklaying?" is misleading. Bricklaying uses mortar to bind the bricks together, not concrete. Concrete is a structural material used for foundations, slabs, and other load-bearing elements. Mortar is weaker and more workable. Therefore, I'll address how to make mortar for bricklaying. Concrete mixes are varied depending on the strength needed, and are not generally used for laying bricks.
Mortar for bricklaying is typically made with a mixture of cement, lime, and sand. The proportions can vary depending on the application and desired properties.
Typical Mortar Mixes for Bricklaying
Here's a breakdown of common mortar mixes used in bricklaying:
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Type N Mortar: A general-purpose mortar suitable for above-grade applications. It offers a good balance of strength and workability. A common mix ratio is 1 part cement : 1 part lime : 6 parts sand.
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Type S Mortar: A high-strength mortar suitable for below-grade applications or where high wind or seismic loads are a concern. A typical mix ratio is 2 parts cement : 1 part lime : 9 parts sand.
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Type O Mortar: A low-strength mortar suitable for interior, non-load-bearing applications. A common mix ratio is 1 part cement : 2 parts lime : 9 parts sand.
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Type M Mortar: A high-strength mortar suitable for heavy loads. It is not commonly used in residential construction due to its lower workability. A common mix ratio is 3 parts cement : 1 part lime : 12 parts sand.
It is important to note that Type M mortar can be more prone to cracking with certain types of bricks. Type S is generally a safer, more useful, high-strength choice.
Steps to Mix Mortar
- Gather Your Materials: You'll need cement (typically Portland cement), lime (hydrated lime), sand (masonry sand or brick sand, which is finer than regular concrete sand), water, and a mixing container (mortar tub or wheelbarrow) and shovel/hoe, or a mechanical mixer.
- Dry Mix the Ingredients: In your mixing container, combine the cement, lime, and sand in the appropriate ratio for the type of mortar you're making. Mix thoroughly until the mixture is a uniform color.
- Add Water Gradually: Slowly add water to the dry mix while continuing to mix. Add enough water to create a plastic, workable consistency. The mortar should be stiff enough to hold its shape but still be easy to spread with a trowel. Avoid adding too much water, as this will weaken the mortar.
- Mix Thoroughly: Continue mixing for several minutes to ensure all the ingredients are well combined and the mortar is a uniform consistency.
- Let it Slake: Allow the mortar to sit for 10-15 minutes after mixing. This process, called slaking, allows the lime to fully hydrate and improves the mortar's workability.
- Re-temper: After slaking, mix the mortar again briefly to restore its workability.
Important Considerations:
- Use clean water: Dirty water can weaken the mortar.
- Use masonry sand: Masonry sand is specifically graded for use in mortar and plaster.
- Mix in small batches: Mortar will begin to harden after a few hours, so only mix what you can use in that time.
- Wear appropriate safety gear: Cement and lime are caustic and can irritate the skin and eyes. Wear gloves, eye protection, and a dust mask when mixing mortar.
