Key Ingredient in Concrete – Portland Cement

Portland cement is the most common type of cement and typically originates from limestone.  It is the key ingredient in concrete, mortar and stucco and used throughout the world.  When added to concrete, it is the paste that binds the aggregate (consisting of gravel and sand) with the water. 

Placing Concrete in Extreme Temperatures

At The Conco Companies we have years of experience placing concrete in all kinds of weather conditions.   We are often asked if it is ever too cold or too hot to safely place concrete.   The answer is not necessarily a “yes” or “no” but rather other factors are taken into consideration. 

What's the Difference Between Cement and Concrete?

Concrete is one of the most utilized man-made materials on the planet. Used for buildings, sidewalks, and infrastructure worldwide, concrete is a hearty material comprised of a mixture of aggregates (any coarse particles used in construction) and paste. Common concrete aggregates include sand and gravel and common pastes are composed of water and cement. That’s right, contrary to popular belief; cement is actually an ingredient in concrete itself.

Although the terms are often used interchangeably, concrete and cement couldn’t be more different. Concrete is the material that we know and love, whereas cement is simply a binding agent used in approximately 15% of concrete to create its signature hardness. Cement is typically composed of finely ground limestone, silica, alumina, and iron oxide.

Types of Cement

There are two common forms of cement: hydraulic and non-hydraulic cement. Hydraulic cement hardens when it comes into contact with water and ultimately forms a water resistant barrier. This is the kind of cement most people are familiar with. Non-hydraulic cement does not harden when in the presence of water. The most common form of cement used in concrete, Portland cement, is a form of hydraulic cement. While most forms of Portland cement are very similar, there are varieties of cement which can be used for specific construction needs:

• Sulphate-resistant cement
• Rapid hardening cement
• Air Entraining cement
• Colored cement
• Low-heat cement
• Hydrographic cement
• Blast furnace slag cement
• White cement (created by using materials with no grey raw materials, such as iron or manganese)
• Quick setting cement

Conco’s mission is to be the best supplier of concrete services in the Western United States and to bring expertise, experience and quality to each project.  We continue to upgrade and expand facilities to better serve the growing market for public works projects, commercial, parking structures, educational, and other construction development. We serve California, Washington State, Oregon, Colorado and Nevada.

Understanding How the Aggregate Influences a Concrete Mix

The Portland Cement Association (PCA) states that, “Aggregates strongly influence concrete's freshly mixed and hardened properties, mixture proportions, and economy.”   Furthermore, while choosing the proper aggregate in a concrete mix is important, the type of aggregate used affects the concrete more while it is wet than once it has cured. 

Concrete mixes are made up of aggregate, cement, water, and sometimes chemical admixtures.  The aggregate’s size or type of stone used in the mix can impact the strength, durability, workability, hardening, and ultimately the cost of the concrete.  It also accounts for up to 60 to 75% of the volume and 70 to 85% of the weight.

Most aggregate comes from sand, gravel or crushed stones and helps to determine the amount of cement paste added to the mix, which is the most costly part of concrete.   Before the aggregate is ready to go into the concrete, it is put through a cleaning and grading process.  Fine aggregate is usually defined as a mix of natural sand or crushed stones with a majority of particles smaller than 3/16th of an inch or 5mm (although sometimes it is defined as less than 4.75mm).  For coarse aggregate, the crushed stones or gravel particles are usually larger than 3/16th of an inch or 5mm (or larger than 4.75mm.).     

Aggregate used in concrete is derived from natural sand or gravel pits, rivers, seas or lake beds, hard-rock quarries, and underground mines.  If the gravel used in an aggregate is extremely rough or irregularly shaped, it will require that more water and cement be added to the concrete mix for a proper consistency.

During our many decades in the industry, The Conco Companies have encountered and successfully used a variety of concrete mixes including “green” concrete.  See our website to learn more about our large portfolio of projects.    

At Conco, we are one of the leading concrete contractors in the Western U.S. and offer a wide range of quality services and products.  Our experience includes providing services for commercial, educational, parking and other construction development as well as public works projects.  We serve California, Washington State, Oregon, Colorado and Nevada.

Source: cement.org/cement-concrete-basics/concrete-materials/aggregate