How to Determine the Temperature of Freshly Mixed Hydraulic-Cement Concrete and Why it is Important

How to Determine the Temperature of Freshly Mixed Hydraulic-Cement Concrete and Why it is Important

In the civil materials testing industry, there are several testing methods that can be applied at construction sites. This article will focus on the testing method that is used to determine the temperature of freshly mixed hydraulic-cement concrete. There are time-dependent requirements for the temperature of concrete that is being used in new construction. In testing the temperature of the concrete, it is ensured that the material will meet these requirements so that it can solidify in a given period of time and can be used safely in construction.

This testing process involves a container, temperature measuring device, and partial immersion liquid in glass thermometers. According to the ASTM standard for the testing method for the temperature of freshly mixed hydraulic-cement concrete, the temperature measuring device should be placed about 3 inches deep into the fresh concrete. After a period of time between 2 and 5 minutes has passed, the temperature measuring device should be removed and the temperature should be recorded. The recorded results from the test are then charted and compared to the appropriate standard specification for freshly mixed concrete to determine if it is safe to use in construction depending on the project’s time constraints.

If the concrete is determined to be too cold or too warm, the variation in temperature affects the rate at which the concrete sets up or solidifies. When the temperature of the material is known, the contractor utilizing the concrete will know how long the concrete will take to set so that they can safely and effectively plan the finishing processes for the project.

By testing the temperature of freshly mixed hydraulic-cement concrete, it is assured that the pre-determined standards are being met, resulting in the safety and longevity of the structure. It can also result in saving time and money, as the construction schedule and budget are among the most important things that can be adhered to throughout the project. Civil materials testing gives the construction project manager peace of mind as they work to meet their own budget and deadline restraints. Encorus’s Civil Testing Group performs testing for determining the temperature of freshly mixed concrete, as well as other concrete testing services, both in the laboratory and in the field.

If you have a need for determining the temperature of freshly mixed hydraulic-cement concrete or any other civil materials testing service, reach out to Civil Laboratory Supervisor Jeremy Lake at (716) 592-3980 ext. 133, or jlake@encorus.com.

How Cold Weather Impacts the Structural Integrity of Concrete

How Cold Weather Impacts the Structural Integrity of Concrete

As a Western New York-based firm, we are no strangers to cold weather. The temperature has a daily impact on our lives, from what clothes we wear to how long our morning commute will take. Just as the temperature has an impact on us, it also has an impact on construction materials, specifically concrete. Exposure to extreme temperature lows can have adverse effects on the structural integrity of concrete.

The temperature should be controlled throughout both the concrete mixing and placement processes. Temperature control during these phases prevents thermal contraction and shrinkage later on in the concrete’s lifespan. According to the ACI 306R-88 standard, exposure to extreme cold during placement can cause rapid moisture loss from warm concrete heating the surrounding cold air, resulting in a reduction of relative humidity. The decline of water content in the concrete can lead to extended setting periods and variation in concrete strength, which could have detrimental effects on the schedule, budget, and safety of the construction project.

Fortunately, practices and procedures have been developed to protect the concrete from being damaged or structurally compromised as a result of freezing. According to the American Concrete Institute (ACI) Cold Weather Concreting (ACI 306R-88) standard, the goal of these cold weather preventative practices are as follows:

“Prevent damage to concrete due to freezing at early ages,… assure that the concrete develops the required strength for safe removal of forms, for safe removal of shores and reshores, and for safe loading of the structure during and after construction,… maintain curing conditions that foster normal strength development without using excessive heat and without causing critical saturation of the concrete at the end of the protection period,… limit rapid temperature changes, particularly before the concrete has developed sufficient strength to withstand induced thermal stresses,… [and to] provide protection consistent with the intended serviceability of the structure”

As listed in the ACI 306R-88 standard, the methods of protecting new concrete include covering the concrete with insulating materials, creating an enclosure surrounding the concrete, using embedded thermal coils to heat the concrete internally, covering the placed concrete with tarps, and implementing insulated forms during the setting period.

Just as preventative measures are necessary to protect the concrete during the construction process, it is also necessary to make sure that the protection methods were effective, which can be achieved through materials testing. Compressive strength is one of the indicators to determine if the concrete meets structural and safety standards. This test is performed by applying an increasing amount of pressure to a piece of material to determine how much weight it can handle before fracturing. Depending on the purpose of the concrete (flooring, foundation, structural support, etc.), there are different standards of pressure that the material is expected to withstand to be considered fit to support the intended load. Encorus’s Civil Testing Group performs laboratory compressive strength testing for a variety of construction materials, including concrete core samples.

If you have a need for concrete testing or have any questions about the impacts of temperature on the structural integrity of concrete, contact Civil Laboratory Supervisor Jeremy Lake at (716) 592-3980 ext. 133 or jlake@encorus.com.

Why Concrete Testing is Essential for New Construction Projects

Why Concrete Testing is Essential for New Construction Projects

Concrete is one of the most common materials that is used in construction as the building blocks for the foundations of various structures around the world. These structures could be as large and complex as your office high-rise or as simple as the sidewalk that you use every day. Regardless of the size or use, it is of the utmost importance that the concrete has been tested by a qualified civil materials testing company. It can be argued that there are three main requirements when it comes to construction projects: efficiency, functionality, and safety. Concrete testing plays a major part in each of these three aspects.

As detailed in Encorus’s previous Fun Fact Friday article, civil materials testing is financially invaluable when it comes to construction projects of any size. Most flaws in concrete can be corrected within the a certain time frame and budget if they are identified early on. This allows the construction team to maintain the client-set standards for finances and scheduling, thus creating a high level of efficiency. If you are interested in learning more about how civil materials testing maximizes construction schedules and budgets, click here.

Functionality gives each construction project meaning and defines the intended purpose of the structure. If a slab of concrete is intended to be used as flooring, it should be evaluated to make sure that it can support the load and traffic that it will be subject to post-construction. In testing the concrete to make sure it can fulfill its intended purpose, it guarantees the functionality of the structure.

Public safety is one of the top priorities in the construction of any given project. It is important to test concrete structures to ensure that they are safe in regards to load-bearing, stability, and any other factors that could come into play. If concrete is being used to support a bridge, civil materials technicians test the strength of that concrete to make certain that it will not put the safety of the public on the line by cracking, crumbling, or failing in any other way.

Encorus’s concrete services include concrete field inspections, compressive strength testing, and concrete mix design verifications. If you have any questions about or need for concrete testing, contact Encorus’s Civil Laboratory Supervisor, Jeremy Lake, at (716) 592-3980 ext. 133, or jlake@encorus.com.

How Civil Materials Testing Maximizes Construction Schedules and Budgets

How Civil Materials Testing Maximizes Construction Schedules and Budgets

New construction developments are often considered to be high stake projects that require adherence to strict budgets and timelines over the course of the construction period. This creates a necessity for producing high quality work while maintaining budget and scheduling requirements.

The construction industry produces heavy pressures to complete work within the given time and budget, and project managers are expected to take measures to ensure that the work will be satisfactorily completed according to predetermined client standards. If there is an unidentified issue with the site or the materials being used, it will likely lead to a waste of time and expenses. This waste is unnecessary and can be avoided by testing the materials for flaws before or during the construction process.

Having the materials tested by a qualified technician beforehand is a preventative process that is timelier and more financially efficient than if any flaws were to go undetected, and then found at a later time, which would lead to backtracking in the project and the unwarranted expenditure of time, money, and materials.

If a flaw is detected by a qualified technician in the early stages of construction, the faulty material can be quickly replaced without the need to undo any other completed construction work. The cost of hiring a civil materials technician is a fraction of the time and financial cost of faulty materials, especially if it goes unnoticed in the long run, which would produce a dangerous structure that would put public safety in jeopardy.

Civil Materials Testing services offered by Encorus in the field include concrete inspections, floor flatness testing, in-place density testing, fireproofing / firestopping inspections, certified welding inspections, ICC special inspections, asphalt testing, wood framing inspection, EIFS inspections, masonry inspection, structural steel inspection, and anchor bolt pull testing.

Encorus also offers a variety of laboratory testing, including compressive strength testing, concrete mix design verifications, grain size analysis, Atterberg Limits Testing, hydrometer analysis, asphalt testing, USCS soils classification, specific gravity testing, and standard / modified proctors.

If you have any questions about how to maximize your construction schedule and budget or require civil materials testing services, contact Encorus’s Civil Laboratory Supervisor, Jeremy Lake, at (716) 592-3980 ext. 133, or jlake@encorus.com.

Fun Fact Friday: Atterberg Limits Testing

Fun Fact Friday: Atterberg Limits Testing

Atterberg Limits Testing is just one of the testing methods that Encorus’s Civil Testing Group uses to determine properties of soil. According to ASTM International, Atterberg Testing Limits are six limits of consistency in soils that were defined by Albert Atterberg. These limits include the upper limit of viscous flow, the liquid limit, the sticky limit, the cohesion limit, the plastic limit, and the shrinkage limit. In modern engineering, the term Atterberg Limits commonly refers to only the liquid limit, the plastic limit, and in some cases, the shrinkage limit.

The liquid limit of soil is the minimum amount of water that would be added to a set amount of soil to change its consistency to a liquid state, meaning that the soil cannot retain its shape. The liquid limit of soils can be determined by creating a paste using soil and a small amount of water and putting it in a liquid limit device. The paste is separated into two halves using a grooving tool, and then allowed to flow together from the shocks caused by repeatedly dropping the device’s cup in a standard manner. This process is repeated with different amounts of water in the paste and the results are plotted on a graph to establish the liquid limit.

The plastic limit of soil is similar to the liquid limit, but it is the amount of moisture that causes soil to display plastic characteristics rather than liquid or solid ones. The plastic limit can be determined using a rolling method where the soil sample with a recorded amount of water is rolled into a 3.2 mm thread and broken into smaller and smaller pieces until it cannot be re-rolled and broken down any more. This process is done twice, and then the average water content of both trials is calculated to determine that soil’s plastic limit. The plasticity index of a particular type of soil can be found by determining the difference between the plastic limit and the liquid limit.

The shrinkage limit of soil is the maximum amount of water in soil that makes it saturated, but still in a solid state. When you add water to soil, the volume increases. However, when a soil sample reaches its shrinkage limit, the volume of the soil does not decrease when the amount of water is decreased even further. The shrinkage limit can be found in a soil sample by determining the relationship between initial wet mass, initial volume, the dry mass, and the volume after drying.

According to the ASTM International Designation: D4318–17E1 , “The liquid limit, plastic limit, and plasticity index of soils are also used extensively, either individually or together, with other soil properties to correlate with engineering behavior such as compressibility, hydraulic conductivity (permeability), compactibility, shrink-swell, and shear strength”. These testing methods are crucial when it comes to determining what type of soil to use as a foundation for construction projects. The properties mentioned above will affect the soil’s ability to maintain its durability under different forms of agitation. Therefore, it is essential for construction professionals to test the soil before starting construction to ensure the long-term integrity of the structure being built.

If you require Atterberg Limits Testing, contact Civil Laboratory Supervisor Jeremy Lake at (716) 592-3980 ext 133, or jlake@encorus.com.

Fun Fact Friday: Qualifications and Importance of Certified Welding Inspectors

Fun Fact Friday: Qualifications and Importance of Certified Welding Inspectors

A certified welding inspector must have a combination of qualifying education and work experience, with documentation to support. According to the American Welding Society, to become a Certified Welding Inspector (CWI), an individual must have both adequate education and sufficient experience. Various levels of education are interchangeable with some years of experience, but by requiring a combination, the certification process ensures that a welder has the knowledge and capability to provide services without fail.

An individual meeting the education and experience criteria is able to apply for and take a Certified Welding Inspector exam. The application must be mailed at least six weeks before taking the exam, and many candidates choose to complete welding inspector training courses to help them prepare for and pass the exam. The exam itself is divided into 3 parts: fundamental knowledge, practical evaluation, and codebook navigation.

The fundamental knowledge section of the exam includes information on various welding processes, heat control & metallurgy, weld examination, welding performance, terminology, relevant welding and non-destructive examination (NDE) symbols, NDE methods, documentation, safety, destructive testing, cutting, brazing and soldering. Succeeding in this section of the exam proves that a welding inspector has the necessary levels of knowledge.

The exam also includes a practical evaluation section, where a welding inspector must demonstrate skill in procedure and welding, mechanical testing and determining properties, welding inspection and determining flaws, non-destructive examination, and utilization of drawings and specifications.

The third and final section of the exam, codebook navigation and applications, is exactly as it sounds. In this section a potential welding inspector must prove their ability to navigate various code books and apply the various codes as required by a project. This skill is critical to ensuring that welding inspections will be completed in compliance with regulations and will be able to adequately ensure the safety of people in the vicinity of the equipment having been welded.

Additionally, anyone seeking a certification must pass a vision test, to ensure they are able to adequately visually inspect welds.

Becoming a Certified Welding Inspector is a complex and challenging process, but this ensures that welding inspection services are provided to a high standard of quality.

If you have a need for Certified Welding Inspections, please contact Jeremy Lake at (716) 592-3980, ext. 133, or at jlake@encorus.com. For more information about our Testing and Inspection Group, please visit https://www.encorus.com/civil-materials-testing/.