This is a column version of the cement calculator that lets you estimate how much cement you need for column shaped concrete elements based on their dimensions. Using the concrete - column calculator you can also find out their volume and weight. Cement is usually sold in bags. If you know the size of the bag, our calculator will help you decide how many bags you need to buy for your project. If you would like to estimate the amount of cement you need for differently shaped elements, check our sibling concrete calculators for tubes and slabs. Use the cement calculator right away or read below to find out how to figure concrete for yourself or how much does a yard of concrete weigh.
How to figure concrete
- First, you need to estimate dimensions of your column shaped elements. Provide the diameter and height of your concrete column.
- Then determine the number of columns you need.
- Based on this data our cement calculator will count the overall volume of all those elements. It is given in cubic yards as default.
- Provide the density of concrete you will use (you will find it on the bag - which is how cement is usually sold - we provided a commonly occurring value, but it varies). You can also check out how to calculate density here.
- Specify the weight of one bag of cement - again check out the bag.
- Account for waste and spillage (5-10% usually) and voila! Now you know how many bags you truly need.
All dimensions are given in default units. You can change them to any other unit by simply unlocking the field (the padlock button).
An example calculation
So let's say we have 2 concrete columns 1 feet in diameter and 4 feet high each. Pre-mixed concrete is usually sold by the cubic yard and this is the volume unit we use by default, but construction elements are usually measured in feet. Therefore our calculator shows the volume in cubic yards - in our example 0,23 cu yd. 4 cubic yards equals 6,28 cubic feet.
Once we have the above measurements all that is left to do is to:
- Check if the density of concrete from a particular producer is the same as the default value in our calculator (150 lb/cu ft). Feel free to change it if you need.
- Now you already know the total weight of the needed concrete.
- Check the weight of a single bag of cement - our default is 60 lb. If not, again, change it to appropriate number.
- To be safe, account for spillage and waste. Experienced contractors usually assume 5-10%.
In our example we'll calculate using default measures. We need 6,28 cubic yards of cement, our producer sells cement in bags weighing 60 lb with a 150 lb/cu ft density. Total weight of concrete that we need is 942,53 lb. We assume 5% of waste and spillage. There you go, we need 17 bags of cement.
How much does a yard of concrete weigh?
The simplest answer to this is: it depends. Precisely, how much a yard of concrete weighs depends on density.
Concrete is a mixture of cement, various aggregates (rock and sand), and water. At times it also contains slag, fly ash, and other admixtures enhancing its properties. Its density depends on a number of variables, namely: the content of cement and water, the amount (and density) of the used aggregate, and the amount of entrained air.
Common concrete densities are:
- Heavyweight concrete - 5130 to 7020 (190 to 260 lbs/cu ft).
- Standard weight concrete - 3915 lbs per cubic yard (145 lbs per cubic foot).
- Lightweight concrete - 2565 to 3132 lbs per cubic yard (95 - 116 lbs per cubic foot).
Heavyweight concrete is produced using heavy natural aggregates, such as magnetite (up to 60% increase in density) or barites (up to 45% increase in density), or manufactured ones: iron or lead shot (from 68 to 154% increase in density). It is usually used for constructing radiation shields (both nuclear and medical). Its properties include: high modulus of elasticity, low thermal expansion and creep deformation.
Lightweight concretes are more porous then the standard ones and manufactured with the addition of pumice, scoria, expanded blast-furnace slag, vermiculite and clinker. It reduces the dead load and increases the speed of building therefore decreasing costs. It also has high fire resistance, has better shock and sound absorption and is characterized by reduced shrinking. There are several types of lightweight concrete. They are commonly used for screeds and walls in buildings, insulation on roofs or for water pipes, precast blocks or panels.