Site-mixed concrete can be a low-cost option if the project is small, and it also offers complete control over adjustments; however, this can become a problem if not mixed properly. Here are some reasons to avoid on-site concrete mixing and consider better options, such as ready mix concrete delivery.

Concrete Quality Can Be Inconsistent

The major factor upon which concrete is judged is its quality. In site-mixed concrete, the quality relies hugely on the experts mixing the concrete on-site.

Any miscalculations or mixer problems can directly impact the strength, consistency, and workability of concrete. And even if one batch comes out according to the requirements, it doesn’t warrant that the next batch will be of the same quality due to many factors.

Requires Space And Equipment On-Site

You will need to have a controlled storage space near the site to store the raw materials and then you will also need space for mixing concrete. This includes space for the mixer, the laborers to carry out the process, and then move it to the site that requires it.

If you have enough space on-site, this may be fine, but on construction sites, especially urban, space is limited. So, this extra requirement of creating space for concrete raw materials and concrete mixing may make things difficult. And if concrete is not stored properly or mixed properly due to space restrictions, it can directly impact concrete quality and also the safety of the people working on-site.

Weather And Humidity Affect Concrete Quality

Weather and humidity levels are two of the factors that impact concrete quality. In contrast to ready-mixed concrete that is manufactured in a weather-controlled facility, site-mixed concrete is made on the construction site, so the weather and humidity levels play a role in the end result, which is the quality of concrete.

For instance, in warm weather, there is a higher evaporation rate during mixing. This can lead to mistakes in keeping the desired water-cement ratio of concrete for the project.

Incorrect Water-Cement Ratio

Water-cement ratio is another big factor that impacts concrete quality, strength, and workability. Usually, a ratio of 0.4 to 0.6 is considered ideal for most projects, but it can be a bit lower or higher depending on the project’s requirements. However, whichever value it is, it should be exactly that.

Many things can cause an unintentional alteration in the water-cement ratio and weather is not the only factor that affects the water-cement ratio.

Using wrong or inaccurate tools, not factoring in aggregate moisture, inaccurate additive proportions, incorrect mixing techniques, adding water unnecessarily as a shortcut, and other factors leave the concrete mix with either too much water (segregation, bleeding, and cracking) or very little water (lower workability, improper hydration, and strength issues).

Not Practical For Large Projects

Site-mixed concrete is good for small projects like building a small patio or repairing stuff, but it’s almost never an effective or efficient option for larger projects. This is because large projects require concrete in substantial volumes and preparing that much on-site will make things unnecessarily complicated.

It will negatively affect productivity and only increase costs. This is one of the reasons ready-mixed concrete is favored in any large project that includes major home improvements as well. It saves time and ensures consistent quality.

Slower Process

You would think that mixing concrete on-site would produce faster results because the concrete won’t need to be transported to the site, but it still takes more time than ready-mix concrete.

The reason is that on-site concrete mixing is done in small batches and the equipment used is not as advanced as that in the concrete manufacturing facilities. Moreover, there are many steps to perform, like measuring the ingredients, moving them to the mixing site, and then mixing the concrete for the required time. And then, you need to move concrete to the site where it’s needed.

In addition to that, issues like miscalculation, mixer breakdowns, and weather conditions can also slow this process down even further. So, the on-site concrete mixing process is slower and it may feel even more slower if large volumes of concrete are needed. Therefore, contact a concrete supplier Gaithersburg for ready-mix concrete.

The Process Is Labor Intensive

When mixing concrete on-site, you will need more laborers on-site because with on-site concrete mixing, the job is not only to pour concrete, it’s also to prepare or mix concrete. So, dedicated laborers will be needed for handling the raw materials, measuring them, loading them into the mixer, operating the mixer, and then moving prepared concrete where required.

As you heavily rely on manual manpower, any errors can affect concrete’s quality. This means you will need experienced and skilled workers, and in required numbers, so they don’t overwork, because longer than usual shifts can also lead to errors.

Material Wastage

We mentioned earlier that the on-site concrete mixing process involves multiple steps. Raw materials are transported to the site, they are mixed, and then transported to another site. This is done manually and in small batches, so spills are a given. The steps are manual so miscalculations can lead to using more materials than required. If there is a bad batch due to errors, it may also need to be discarded, which only increases wastage.

On top of that, improper storage practices can lead to raw material contamination. For instance, if not stored in a dry and controlled area, cement may absorb moisture and become hard. This will make it unfit for concrete mixing and you will have to discard it.

Risk Of Cost Increase

Site-mixed concrete is cost-effective compared to ready-mixed concrete for smaller projects because there are no transport charges and no minimum order requirements involved.

However, if the project is medium-sized or large, mixing concrete on site may not be as cost-effective, as there will be skilled laborers required for mixing concrete, there will be spillage, any errors can lead to a bad batch that will need to be discarded, and poor concrete quality can lead to structural problems and project failure.

Poor Testing

Concrete testing is an important step that ensures that the manufactured concrete meets the set requirements. In on-site concrete mixing, quality control and testing are huge challenges.

Many times, testing methods are not implemented properly. Common tests like slump testing, strength testing, and materials testing are not carried out as frequently and when performed, there is a higher risk of inaccurate results due to improper tools or inexperienced workers.

With poor quality control, the risk of using concrete with bad quality is high, which can put the entire project into jeopardy.

Conclusion

On-site concrete mixing offers a few benefits, such as being good for small projects and remote areas, having complete control over the concrete design, and not having to pay for transport fees. However, there are many issues that make it an unfavorable choice for medium and large construction projects, such as its time-consuming, labor-intensive nature, inconsistent concrete quality, and it requires reserved space for materials and equipment. So, if your project is medium-sized or bigger, a better option is to choose a ready mix concrete supplier Rockville to get quality RMC delivered to your site.