Concrete Mix Proportions

What Is The Difference Between Concrete & Cement

Concrete is the finished product of everything mixed together. Cement is one of the ingredients used in the mix. It is the glue that holds everything together and water is the thing that activates and facilitates the hardening process.

How Much Water To Mix With Concrete

One of the most important parts of mixing concrete is the amount of water that is used in the mix. It is common for beginners to add too much water to the mix which almost completely depletes the strength in the final product.

Common Concrete Mixes

Standard Concrete Mix
1 part type 1, type 10 or type N portland cement (the name will depend on where you are located)
2 parts coarse sand
3 parts gravel (3/8", 1/2" or 3/4" size)

This mix is the go-to standard for concrete mixes. It is the cheapest mix by volume and can be adjusted for strength, set time or any number of factors by adding various admixes such as calcium, liquid acrylic, bonding agent or integral colors. This concrete mix is best mixed to a wetter consistency, a slump of 3-10", and a drum style concrete mixer can batch this type of concrete efficiently and easily. This concrete should not be mixed with a mortar mixer and care must be used to use a drill and paddle to mix this concrete in a bucket.

Mortar Mixes

Mortar mixes are sand and cement with no larger stones in the mix. Mortar is a form of concrete and is simply one of many variations to change the setting or finishing properties of the material. for projects where larger volumes of concrete are required a simple mortar mix may be ideal.

Also called grout, plaster, slurry and mud and sand and cement concrete mix is a mortar. The uses for mortar mixes are enormous ranging from stucco to swimming pools to tile setting to repairs to detailed or decorative concrete work. Learning the basics about mortar mixes opens up a world of projects that you can apply the knowledge to.

The strongest mortar mix is three parts coarse sand and one part cement. This produces a very workable concrete mortar that is quite strong. With no additional ingredients this mix will produce reliable and strong results time and again. By adding admixes you can significantly alter the strength and unique properties of this mix extensively.

A concrete of one part cement and one part sand would be surprisingly weak. The cement needs the aggregate, in this case sand, to glue together for strength. A mix of two parts sand to one part cement is strong enough for most applications and can be finished to a fine detail due to the soft texture of this mix. This mix is also highly modifiable.

Mortar mixes above four parts sand to one part cement become weak very quickly. Anything over six parts sand to one part cement is very weak and can only be used for specialty applications. A mortar mix of six or seven parts sand to one part cement would be common for stacked block retaining wall construction and wet set interlocking stone installation.

Lightweight Concrete Mix

Vermiculite can be substituted for sand in a mortar mix in partial or full quantity depending on the application. A concrete mix of three parts sand to one part cement is very strong. If you were to replace one unit of sand for a unit of vermiculite, the strength of the concrete would go down noticeably and it would only be somewhat lighter.

If you replace the sand completely with vermiculite the finished product concrete will be near to half the weight of a three to one mortar, but would only be about 20% the strength of a three to one mortar mix. Experimenting is crucial if you want to begin creating items and working seriously with lightweight concrete as this will help you to understand the limitations it has.