The recipe for making concrete is very simple.
When Portland cement is mixed with water a chemical reaction takes place which makes the cement harden. In doing so it binds together the sand and gravel mixed with it to become one solid rocklike mass.
Many varieties of cement are made of which five are commonly used and available at most suppliers.
STANDARD CEMENT. This is ordinary grey cement. Used for all general construction. If you don't specify otherwise this is what you will get when you buy cement.
WHITE CEMENT. Similar in all properties to standard cement except that it is white in color. Used to mix light colored concrete and mortar and for making colored cement.
HIGH EARLY STRENGTH CEMENT. Hardens and develops strength much faster than standard cement. Allows quick use of driveways and walks.
AIR ENTRAINED CEMENT. This is not as strong as standard cement but has high resistance to frost and salt. Useful where salt is applied for ice and snow removal.
MASONRY CEMENT. A special mixture for use with sand to make mortar. Has more plasticity,water retention and ease of handling.
The type of concrete mix is expressed by three numbers such as 1:2:4 which means 1 part cement, 2 parts sand and 4 parts gravel or stone. To make good concrete you must measure ingredients accurately.
If you don't want to mix your own you can buy,at somewhat higher cost,prepackaged mixes. These contain the right proportion of ingredients to which you only need to add water.
Concrete can be mixed by hand on a plywood sheet at least 4 by 6 feet. It can also be mixed on a
concrete sidewalk or driveway. Mix the cement and sand till completely blended then add the gravel and mix till coated with cement. Make a crater in the middle of the pile and pour in about half the measured amount of water. Rake the sides of the pile up and into the water. When all the water is absorbed make a new crater and add the rest of the water.
Mixing large amounts of concrete by hand is hard work. It is better to buy or rent a concrete mixer if you need a lot of concrete. These instructions for how to make concrete are very simple and will provide you with good concrete.
You can also make your own concrete blocks using hand made molds. This is a great home business opportunity. Concrete blocks are always in strong demand everywhere and you can have a home part time business supplying them to building supply stores or directly to consumers.
Working from your garage your costs are very low and you can turn out a quality product at a very competitive price. When you reach the stage of needing increased production you can build a concrete block making machine from auto parts and sheet metal
This home built concrete block machine can turn out 800 or more blocks per day and is every bit as good as a commercial model which costs thousands of dollars. Plans and instructions for making the machine and the hand molds are readily available.