how much cement do i need

Essential concrete basics for using a concrete calculator

Before using a concrete calculator, it is helpful to understand what concrete is so any estimations you make can be as close to reality as possible. Concrete is a composite material used for all kinds of construction projects, especially where high compressive strength is required. It is composed of fine and coarse aggregate which are bonded via fluid cement paste that hardens over time – usually about a week to reach over 50% of its final strength and a couple of weeks to reach 95% of it. Completely settling in place might take several years, depending on climate and other conditions.

Cement transport

We use cement tank trailer transport cement. The common cement trailer is cement bulker for sale, powder tanker for sale.

Most concretes in construction are lime-based, such as Portland cement concrete or calcium aluminate cement. Road construction is an exception since in asphalt concrete the cement material is bitumen. Polymer-based concretes are seldom used. Most concrete is embedded with reinforcing materials (e.g. rebar) which provide tensile strength (which concrete lacks on its own) resulting in reinforced concrete.

Different concretes may exhibit highly variable density which is an important part of estimating the amount of concrete you need. For example, Portland cement concrete holds water, but other types of concrete called “Pervious concrete” allow water to pass, making storm drains unnecessary. These two types of conrecte would naturally have vastly different densities. Our concrete calculator allows you to specify custom concrete density for accurate results.

How to Calculate Concrete

Concrete, which is a mix of water, aggregate, and cement, is most commonly sold by the cubic yard but is also available in pre-mixed bags.

Concrete is used for many construction purposes, including foundations, stem walls, patios, or driveways. It’s also used to fill CMU blocks or to create countertops.

It’s important to calculate the amount of material needed as accurately as possible. Concrete must be poured at the same time; if you don’t have enough concrete for the pour, the resulting installation can be weak or need to be redone.

We’ll cover the process for estimating concrete in detail below, but you can also use the calculator above to simplify the process.

What equation should I use to find out how much concrete I need?

How to calculate concrete:

Determine how thick you want the concrete

Measure the length and width that you’d like to cover

Multiply the length by the width to determine square footage

Convert the thickness from inches to feet

Multiply the thickness in feet by the square footage to determine cubic feet

Convert cubic feet to cubic yards by multiplying by .037

Here’s what the math looks like for a 10’ by 10’ concrete patio:

10 x 10 = 100 square feet

4 ÷ 12 = .33

100 x .33 = 33 cubic feet

33 x .037 = 1.22 cubic yards

Essentially you are solving for volume and then converting to cubic yards. For concrete, the formula for volume is as follows: length x width x thickness.

To determine how many bags of concrete you will need, divide the total cubic yards needed by the yield.

Use the following yields per each bag size:

40 pound bag yields .011 cubic yards

60 pound bag yields .017 cubic yards

80 pound bag yields .022 cubic yards

What is cement?

Cement is a reactive powder component that binds fine and coarse aggregates together with water. Water and cement react together and harden to form a durable yet brittle material. Cement is made out of pulverized and crush stones mixed with chemicals such as lime and calcium silicate.

Cement can be categorized into two main types depending on how it reacts with water. Hydraulic cement sets and hardens in the presence of water and remains durable and tough after hardening. On the other hand, non-hydraulic cement sets in a dry environment in the presence of carbon dioxide and tends to expand and deteriorate after setting, especially when exposed to water. Because of that, non-hydraulic cement is usually used for indoor purposes only.

In our modern construction industry, we now mostly use hydraulic cement for indoor and outdoor uses. Portland cement, particularly, is the most common hydraulic cement around the world, so, in this calculator, we focus mainly on Portland cement and its different uses.

Different applications of cement

When talking about cement, the word concrete usually also comes into play. And though they might seem the same, they are indeed two different things. Concrete is produced by mixing cement with water, fine aggregates like sand, and coarse aggregates like gravel. Cement binds everything together to form concrete.

On the other hand, by mixing just cement, sand, and water, we create mortar. Mortar is used for joining together concrete blocks or bricks. Adding more water to a mortar mix makes it suitable for plastering concrete block walls or for using as a thinset for adhering tiles. By adding water, we can make a thinner and smoother mix that can be troweled to finish a surface. You can learn more about mortar and thinset in our mortar calculator and our thinset calculator, respectively.

Cement is also used in making grout mixtures. We use grout to fill in the gaps between tiles and even between bricks. However, nowadays, we can already buy pre-mixed cementitious dry grout in bags for convenience. If you want to learn more about grout and would also love to know how to calculate the volume of grout needed for a tiling project, you can check our grout calculator.