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: Control Systems Engineering

Fun Fact Friday: Control Systems Engineering

One of the lesser known services that Encorus Group offers is control systems engineering design. This discipline is relatively broad, so Senior Electrical Engineer Tom Gilmartin elaborates on when control systems engineering is widely used, which is in the manufacturing process.

A manufacturing process can be thought of as a lineup of equipment in a factory used to produce a product. The product can be anything, from orange juice to airplanes. The process usually includes equipment such as pumps, motors, fans, robots, conveyors, and the like. Typically, a process engineer designs how the system is to function, determining how much of which item (water, chemicals, parts, powder, etc.) has to move where in the system.

Once the process engineer has defined the process, mechanical and electrical engineers step in and design a system to perform the process. This might include sizing equipment, designing electrical feeds, laying out the process physically and fitting it into a building.

With the process defined, and the power and mechanical equipment selected, the controls engineer is called in to finalize the process. The controls engineer, with some help from others, selects instruments necessary to make measurements on the process, such as flow, pressure, temperature, etc. The controls engineer designs communications and wiring to allow all the instruments and devices to communicate to an industrial computer. The computer is programmed to run the process, and to monitor its operation. This often includes a “human machine interface” (HMI), typically a computer screen and keyboard, which provides a visual representation of what is happening in the process as it runs. Controls engineers will start up and test the process, adjusting programming as needed to produce the product correctly.

After the process is functional, it is turned over to plant personnel and run by plant operators. Normally the system will operate for 10 years or more, cranking out its intended product. Once the system begins to fail, the procedure of creating a new manufacturing process begins again.

If your company has a requirement for control systems engineering design, contact Director of Engineering Design Services Tom Gilmartin, PE, PMP, LEED AP, at (716) 592-3980 ext. 124, or at tgilmartin@encorus.com.

Fun Fact Friday: Forensic Engineering

Fun Fact Friday: Forensic Engineering

Many people are familiar with the common types of engineering: civil, electrical, mechanical, environmental, structural, and so on. But one discipline that might not be so widely known is forensic engineering, also referred to as investigative engineering.

Forensic engineering can be anything that requires an investigation into the origin and cause of a structure or object’s malfunction. These investigations and subsequent engineering reports are conducted by licensed professional engineers. This type of engineering is more common than most people may think. Insurance companies often call upon professional engineers to investigate claims that people make for some type of damage to their house or building structure. Professional engineers are brought in to analyze the situation and determine if the insurance claim is legitimate, who should pay for the damage, and the possibility and scope of repair. Property owners, plant managers, and others may also request forensic engineering services

Weather-related events such as wind, ice, hail, and snow are frequently the cause of structural damage. Foundation shifting, roof damage, burst pipes, electrical malfunctions, and other structural and equipment issues can be subject to a forensic engineering investigation in order to determine the cause of damage. Fire origin investigations are also common in forensic engineering, in addition to the evaluation of the structural integrity of the building or area involved in the fire. Equipment failures or malfunctions can also be investigated.

Encorus Group has several licensed professional engineers on staff who have experience performing forensic investigations. If you are in need of forensic engineering services, call Tara Lowry at 716.592.3980, ext. 120 or email tlowry@encorus.com.