What documents need to be checked when purchasing concrete?

Although buying concrete might seem simple, there are a few key documents you should review to make sure you get the right kind and quality for your project. Important details regarding the composition, strength, and suitability of the concrete for different conditions are provided by these documents. Making sure all the paperwork is in order can help you avoid future problems such as structural weaknesses, higher expenses, and legal issues.

The concrete mix design is one of the most important documents to review. This details the ratios of the different ingredients used to make the concrete, including water, sand, gravel, and cement. The mix design contributes to ensuring that the concrete satisfies the necessary durability and strength requirements. Verifying that a qualified engineer has approved the mix design is also crucial, as it provides an additional level of assurance that the concrete will function as planned.

Each batch of concrete comes with a delivery ticket, which is another important document. The delivery ticket contains information about the temperature at the time of delivery, the quantity delivered, and the date and time of batching. It might also include details on any additives that were used and the ratio of cement to water, both of which have a significant impact on the concrete’s quality. Examining this ticket will help guarantee that the concrete is delivered in good condition and that it matches the order.

Examining test results, such as compressive strength tests, which attest that the concrete satisfies the necessary performance standards, is also advised in addition to these documents. These tests, which offer an unbiased assessment of the concrete’s quality, are often carried out by independent laboratories. Having access to these reports can help you feel more confident about the materials being used, which can help you prevent structural issues down the road.

You can make sure the concrete you buy is of the highest caliber and fits your needs by carefully going over these documents. This diligence helps to ensure safety and adherence to building codes, while also safeguarding the integrity of your construction project.

How can a concrete seller deceive?

A few private businesses employ multiple strategies:

• Being a third party (in other words, resellers) they substitute documents. They provide the customer with a document for more expensive concrete, and they themselves deliver a mixture of lower quality.
• A significantly smaller volume of concrete is brought in and water is added to it during unloading.
• The mixture is diluted before delivery and the diluted mixture is immediately poured.

Furthermore, dishonest vendors frequently "forget" to deliver the crucial concrete document. It is crucial to keep in mind that the seller is required by GOST to present a high-quality passport that satisfies all requirements and, in the event that the concrete passes the necessary test, a certificate of conformity for the construction mixture. The buyer may refuse payment and cancel the order if at least one of these documents is missing.

Quality passport

This is the primary document attesting to the qualities and attributes of the concrete. Each batch of the mixture produced on the line in a 24-hour period needs to have a quality passport issued in accordance with the standards. The GOST that the concrete mixture satisfies (such as GOST 28013-98 or 7473-2010) must be indicated. Only after laboratory analyses and the necessary testing of the solution have been completed is the document released. The primary document you can use to appear in court if it turns out that the concrete was manufactured with violations is the quality passport, which is also sometimes referred to as a concrete mix quality document.

In accordance with GOST 7473-2010’s paragraph 8.8 regarding the supply of concrete mixes:

• The concrete supplier must carry out delivery in accordance with the relevant contract. It must indicate the quality parameters of the produced concrete mix.
• Before delivery, the customer can request information from the supplier about what materials are used for the concrete mix and their quality. Also, upon request, the manufacturer is obliged to provide data from preliminary product tests.
• The mixture hardening mode and the rate of strength gain can be presented in the form of a curve. It indicates a temperature of 20 ° C and an interval from 1 to 28 days.
• Upon delivery of the finished mixture, the supplier must provide the buyer with a printed and certified passport for concrete with a test report and a consignment note. Additionally, a quality certificate is provided (if it is provided).

Features of filling the passport to concrete

The top portion of the passport needs to state:

• Batch number and volume of the supply of the mixture in cubic meters.
• Next is the name and address of the manufacturer or supplier and the data of the recipient.
• GOST, Mark, the class of the mixture and the date of its manufacture.
• Date and time for sending the mixture. It is very important that the supplier adheres to the correct delivery time and use the appropriate vehicles for this (Read more about this here).

The construction mixture’s test parameters are as follows:

• capacity;
• concrete class for compression for 28 days;
• other quality indicators (for example, in this block, the frost resistance of the composition can be indicated);
• coefficient of variation of the strength in percent;

Wholesome The strength indicator in the project may be 30% lower than what is shown. The test samples from the fourteenth day match this parameter. The 28th day marks the completion of strength gain.

• required strength of the composition in MPa;
• design grade by average density (indicated only for lightweight concrete);
• name and volume of additive (for example, 0.3% Khimkom P-1);
• class of specific efficiency of materials;
• maximum aggregate size.

A completion date and the laboratory head’s signature should appear at the very bottom of the document. The seal of the organization encloses everything.

Practical! Each batch of concrete mix that is delivered should have its own quality document if multiple batches are being delivered. It won’t be evident whether the concrete satisfies the stated characteristics until 100% strength has been attained, so the passport and any supporting documentation must be retained for a minimum of 28 days.

The form pertaining to the quality of the concrete mix can be found in Appendix B of GOST 7473-2010.

When comparing the two options for document completion, this option fully complies with GOST requirements and follows all guidelines. The certification body’s and the laboratory’s seals are present in addition to the organization’s seals.

Additionally, the provider might offer a condensed version. Although the passport example below lacks a few items, it still demonstrates all the necessary features, so this choice is also acceptable. However, it is evident from this passport that the mixture lacks both a quality certificate and proof of laboratory testing.

Examining particular documents is crucial when buying concrete in order to guarantee quality and standard compliance. Important papers include the batch ticket, which confirms the precise mix delivered; test reports or certificates, which attest to the material’s strength and other essential characteristics; and the concrete mix design, which lists the ingredients’ quantities and specifications. By reviewing these documents, you can lower the chance of errors or failures by making sure the concrete satisfies the performance standards needed for your project.

Certificate of Conformity of Concrete Mix

This is an additional crucial document that increases confidence if the manufacturer is prepared to offer a quality certificate. Verify that the passport has this document’s number entered if it is available.

Only after the mixture has successfully completed all required testing is a quality certificate granted. It is imperative that the certification process be executed by an independent licensing body. As per GOST, if information about laboratory tests is included in the quality passport, then an option is acceptable since there is no separate form to fill out and no requirements. For instance, if we take another look at one of the sample forms, we can see that the supplier company, the laboratory, and the certification center have all stamped it.

Certain mixes or all manufactured goods are certified for some manufacturers. When a certificate is issued independently, it typically shows:

• certificate number and its validity period;
• certification body (name of the organization, address and contact information);
• certified products (types of mixtures and their parameters are listed);
• compliance with regulatory bodies (which GOST or TU the product fully complies with);
• information about the manufacturer;
• data on the issuance and basis for issuing the certificate.

The expert and the head of the body have signed the document, which has been sealed and certified. Other formats are accepted as well. It is also important to keep in mind that these kinds of documents come in different forms.

Types of certificates for concrete

Three categories of certification exist:

• Voluntary. Confirms that the manufacturer"s products comply with GOST standards, technical conditions and other regulations. To obtain a voluntary certificate, you must contact an accredited organization and provide all the necessary documents. The main difference from other types of certification is that when receiving a voluntary certificate, the applicant himself lists the criteria by which his products will be assessed. Such a certificate is valid for 1-3 years. Upon expiration of its validity period, the product verification procedure must be repeated.

• According to the form of the QMS (quality management system). In this case, the parameters for checking building compositions are determined not by the customer, but directly by the certification center itself. Accordingly, the requirements are more stringent. If certification is carried out according to the QMS form, then not only the provided sample of the composition is checked, but also audit checks are carried out (the company is notified of them in advance) at the supplier"s enterprise itself. This certificate is more detailed, it describes not only the characteristics of concrete, but also production technologies. If the supplier provides this type of document, it confirms its high competitiveness and guarantees the quality of the purchased concrete mix. The validity period of the QMS certificate is 3 years. To renew it, you must re-pass the audit.

• Sanitary. In certificates of this type, the emphasis is on how safe it is to work with concrete and that it fully complies with the TU. Before issuing the certificate, hygienic tests are carried out in licensed laboratories. Based on the results of the research, the document indicates information about potentially harmful substances in the composition and the intensity with which they can be released into the environment. Additionally, the mixture is assigned a certain area of ​​​​application (for example, that the composition is allowed to be used in the construction of food, pharmaceutical or other industries). The certificate must also indicate the features of safe operation, transportation, and disposal of the material, in accordance with SanPiN. The document must be signed by the chief sanitary doctor and is valid for 1 year. If the certificate is issued in the form of ISO 9001, this means that mixtures from abroad were tested.

Any kind of certification is actually regarded as optional. The differences are found in the document’s validity period and a few features related to sample checking.

Verifying the relevant paperwork before making a concrete purchase is essential to guaranteeing the quality and specifications needed for your project. Verify the supplier’s certifications first. The ISO, for example, attests to the supplier’s adherence to international quality and safety standards. The supplier’s ability to maintain consistent production quality is guaranteed by these certifications.

After that, carefully go over the technical specifications and product data sheets. These records include comprehensive details about the concrete mix, such as its strength, longevity, and any unique characteristics like resistance to chemicals or extreme heat. This data assists you in verifying that the concrete satisfies the particular specifications needed for your project, be it a road, foundation, or another structure.

In addition, request and examine compliance certificates and test results. These documents display the outcomes of tests done on the concrete to make sure it complies with legal and industry standards. Depending on the requirements of your project, these may include tests for compressive strength, which are essential for structural integrity, as well as other pertinent tests.

Lastly, remember how crucial delivery documentation is. This includes the delivery note, which guarantees that the concrete you receive matches your order and provides information on the quantity and type of concrete delivered. Additionally, pay attention to the batch numbers, as they can be used to track and resolve any problems related to individual deliveries.

You can confidently buy the right concrete for your project, avert potential problems, and guarantee a sturdy and long-lasting outcome by carefully going over these documents. This meticulous documentation review guarantees adherence to building standards and regulations while protecting your investment.

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