Calculation of Cement, Sand, Bricks, and Water for 1 Cubic Meter of Brickwork

When it comes to building with fly ash bricks, understanding the precise quantities of cement, sand, and water required for 1 cubic meter of brickwork is crucial for both efficiency and quality. This guide will walk you through the detailed calculations for a 1:4 cement-sand mix using 230mm x 100mm x 100mm brick dimensions.

Volume of Bricks

First, calculate the volume of a single brick:

Size of the Brick: 230mm x 100mm x 100mm 0.23m x 0.1m x 0.1m Volume of one brick: 0.23 × 0.1 × 0.1 0.0023 m3

Next, determine how many bricks fit into 1 cubic meter:

Number of bricks per cubic meter: 1 ÷ 0.0023 ≈ 434.78 Rounding down: 434 bricks

Volume of Mortar

The total volume of brickwork includes the bricks and the mortar. A common assumption is that the mortar occupies about 20% of the total volume. Thus, the volume of mortar can be calculated as follows:

Volume of mortar: 20% of 1 m3 0.2 m3 Volume of bricks: 1 m3 - 0.2 m3 0.8 m3 for bricks

Calculating Cement and Sand

Using the mix ratio of 1:4 cement:sand:

Total parts: 1 4 5 Volume of cement: (1/5) × 0.2 m3 0.04 m3 Volume of sand: (4/5) × 0.2 m3 0.16 m3

Weight of Cement and Sand

To convert volumes to weights, use the typical densities:

Density of cement: 1440 kg/m3 Density of sand: 1600 kg/m3

Calculating the weights:

Weight of cement: 0.04 m3 × 1440 kg/m3 57.6 kg Weight of sand: 0.16 m3 × 1600 kg/m3 256 kg

Water Requirement

The amount of water typically used is about 0.5 times the weight of cement for good workability:

Water: 0.5 × 57.6 kg 28.8 kg 29 liters

Summary of Materials Needed

The quantities of materials needed for 1 cubic meter of brickwork are as follows:

Cement: 58 kg Sand: 256 kg Bricks: 434 bricks Water: 29 kg (approximately 29 liters)

It is important to note that specific site conditions and local guidelines can affect these quantities. It is always recommended to verify with local standards or guidelines.

Here in the UK, a rough rule of thumb is used for quick calculations with a focus on wastage:

Mortar Mix: A mortar gauge of 3:1 will need twice as much cement as a gauge of 6:1. The amount of water will depend on the wetness of the sand and the ambient temperature. Laying Bricks: With a 6:1 mix of mortar and 60 bricks per m2, a tonne of sand and 5 x 25kg bags of cement will allow enough mortar to be mixed for 1000 bricks in a half brick 4inch wall. This works out to approximately 16.5 m2. Smallest Bags: If only 60 bricks are needed, 3 bags of sand (75kg) and 1 bag of cement (25kg) would be necessary, which may be more than required in some situations.

Due to logistical considerations, it is often easier to work with a rule of thumb that accounts for smaller batch sizes and potential wastage.