Concrete inspection

Concrete inspection is the process of evaluating the quality and condition of concrete structures and surfaces. It involves a visual examination and assessment of the concrete to identify any cracks, defects, or other signs of degradation, and to determine the need for repair or replacement. The inspection may also include non-destructive testing methods such as compressive strength testing and sonography. The objective of concrete inspection is to ensure the safety, stability, and durability of the structure.

How to inspect concrete

Concrete inspection involves the following steps:

Visual Inspection: This involves a thorough visual examination of the concrete surface, checking for cracks, holes, and other signs of damage.
Measurement of Concrete Thickness: The thickness of the concrete can be measured using a thickness gauge or by drilling a small hole and measuring the depth.
Evaluation of Concrete Quality: The quality of concrete can be evaluated by checking its uniformity, consistency, and overall appearance.
Non-Destructive Testing: This includes compressive strength testing, impact testing, and ultrasonic pulse velocity testing, to determine the internal condition of the concrete.
Evaluation of Reinforcing Steel: The reinforcing steel in concrete structures should be checked for rust and corrosion, and evaluated for any signs of deformation.
Evaluation of Joints and Cracks: Joints and cracks in concrete surfaces should be evaluated for size, shape, and orientation, to determine their potential impact on the structure.
Testing of Concrete Hardness: The hardness of concrete can be tested using a rebound hammer, which measures the rebound of a hammer after striking the surface.
Record Keeping: All inspection findings should be documented, including photos and detailed descriptions, to provide a comprehensive record of the condition of the concrete structure.

Visual inspection

Visual inspection is an important part of concrete inspection. It involves a thorough examination of the concrete surface to check for cracks, holes, and other signs of damage. During a visual inspection, the inspector will look for the following:

Cracks: Horizontal, vertical, and diagonal cracks can indicate problems with the concrete structure, including settling, shrinkage, and impact damage.
Surface Defects: Pitting, spalling, and scaling of the concrete surface can indicate that the concrete is deteriorating.
Discoloration: Changes in color can indicate exposure to moisture or chemicals, which can weaken the concrete.
Surface Finish: The surface finish of the concrete should be evaluated for uniformity, consistency, and overall appearance.
Deformation: Sagging, bulging, or other forms of deformation can indicate a problem with the structure, such as settling or failure of the reinforcing steel.
Corrosion of Reinforcing Steel: The reinforcing steel in concrete structures should be checked for rust and corrosion, as this can weaken the structure and increase the risk of failure.
Joints and Cracks: Joints and cracks in concrete surfaces should be evaluated for size, shape, and orientation, to determine their potential impact on the structure.

It is important to note that visual inspection is just one step in the concrete inspection process and should be combined with other testing methods to provide a comprehensive evaluation of the concrete structure.

Measurement of concrete thickness

Measuring the thickness of concrete is an important part of concrete inspection. The thickness of the concrete can be measured in a few different ways:

Thickness Gauge: A thickness gauge is a handheld device that measures the thickness of the concrete by sending an electronic pulse through the material and measuring the time it takes to return.
Drilling a Hole: A small hole can be drilled into the concrete and the depth measured with a ruler or tape measure to determine the thickness.
Non-Destructive Testing: Ultrasonic pulse velocity testing is a non-destructive method that can be used to determine the thickness of concrete.

It is important to measure the thickness of concrete accurately to ensure that the structure meets the specified design requirements and to identify any areas of the structure that may be too thin and in need of repair or reinforcement.

Evaluation of concrete quality

The evaluation of concrete quality is an important part of concrete inspection. The quality of concrete can be evaluated by checking its uniformity, consistency, and overall appearance. Some factors to consider when evaluating concrete quality include:

Uniformity: The concrete should be uniform in color, texture, and consistency throughout the structure.
Consistency: The consistency of the concrete should be uniform, with no variations in texture or density.
Appearance: The overall appearance of the concrete should be evaluated, including the surface finish, which should be smooth and consistent.
Strength: The compressive strength of the concrete can be measured using a compression testing machine to determine if it meets the specified design requirements.
Porosity: The porosity of the concrete can be evaluated using non-destructive testing methods, such as sonography, to determine if the concrete is absorbing moisture, which can weaken the structure over time.
Rebound Hammer Test: A rebound hammer can be used to test the hardness of the concrete surface and determine its overall quality.

By evaluating the quality of the concrete, the inspector can determine if the structure meets the design specifications and if any repairs or reinforcements are needed to ensure its stability and durability.

Non-destructive testing

Non-destructive testing (NDT) is a method of evaluating the condition of concrete structures without causing any damage. It is an important part of concrete inspection and can provide valuable information about the internal condition of the concrete. Some common non-destructive testing methods used for concrete inspection include:

Compressive Strength Testing: This involves measuring the compressive strength of concrete using a compression testing machine.
Ultrasonic Pulse Velocity Testing: This method uses ultrasonic waves to determine the density and uniformity of the concrete, and to detect voids, cracks, and other internal defects.
Impact Testing: Impact testing involves striking the concrete with a hammer and measuring the rebound to determine its hardness and quality.
Sonography: Sonography uses high-frequency sound waves to determine the thickness of concrete and detect internal defects, such as voids and cracks.
Rebound Hammer Testing: A rebound hammer can be used to test the hardness of the concrete surface and determine its overall quality.

Non-destructive testing provides valuable information about the internal condition of concrete structures and helps inspectors determine if any repairs or reinforcements are needed to ensure the safety, stability, and durability of the structure.

Evaluation of reinforcing steel

The evaluation of reinforcing steel is an important part of concrete inspection, as it can provide information about the structural integrity of the concrete and the condition of the reinforcing steel. Some factors to consider when evaluating reinforcing steel include:

Corrosion: Reinforcing steel should be checked for signs of corrosion, including rust and pitting, which can weaken the steel and increase the risk of failure.
Adequacy: The reinforcing steel should be evaluated to ensure that it is adequate to support the loads imposed on the concrete structure.
Spacing and Placement: The spacing and placement of the reinforcing steel should be evaluated to ensure that it meets the design specifications and that the concrete will be properly supported.
Size: The size of the reinforcing steel should be evaluated to ensure that it meets the design specifications and that it is adequate to support the loads imposed on the concrete structure.
Anchorage: The anchorage of the reinforcing steel should be evaluated to ensure that it is secure and that the steel will not pull out of the concrete over time.
Concrete Cover: The concrete cover, or the distance between the surface of the concrete and the reinforcing steel, should be evaluated to ensure that it meets the design specifications and that the reinforcing steel is protected from corrosion and other forms of damage.

For more information on rebar inspections check out: Guide to inspecting, sizing, and inspecting rebar

Evaluation of joints and cracks

The evaluation of joints and cracks in concrete is an important part of concrete inspection, as these elements can affect the stability and durability of the structure. Some factors to consider when evaluating joints and cracks include:

Type and Location: The type and location of the joint or crack should be evaluated to determine its potential impact on the stability and durability of the structure.
Size: The size of the joint or crack should be measured and evaluated to determine its potential impact on the stability and durability of the structure.
Pattern: The pattern of the joint or crack should be evaluated to determine if it is consistent and uniform, or if it is irregular and potentially indicative of a larger problem.
Movement: The movement of the joint or crack should be evaluated to determine if it is stable or if it is continuing to grow, which can indicate a larger problem with the structure.
Causes: The cause of the joint or crack should be determined to ensure that it is not indicative of a larger problem with the structure.
Repair Options: Repair options for joints and cracks should be evaluated to determine the best course of action to ensure the stability and durability of the structure.

By evaluating joints and cracks, the inspector can determine if the structure is safe and stable, and if any repairs or reinforcements are needed to ensure its continued safety and longevity.

Testing of concrete hardness

Testing concrete hardness is an important part of concrete inspection, as it provides information about the overall quality and durability of the concrete. Some common methods of testing concrete hardness include:

Rebound Hammer Testing: A rebound hammer can be used to test the hardness of the concrete surface and determine its overall quality.
Schmidt Hammer Testing: A Schmidt hammer can be used to test the hardness of the concrete surface and determine its compressive strength.
Brinell Hardness Testing: Brinell hardness testing uses a steel ball and a load to determine the hardness of the concrete surface.
Rockwell Hardness Testing: Rockwell hardness testing uses a diamond indenter and a load to determine the hardness of the concrete surface.

By testing the hardness of concrete, the inspector can determine its overall quality and durability, and determine if any repairs or reinforcements are needed to ensure its continued safety and longevity. Hardness testing can also be used to detect variations in the concrete that may indicate issues with the mixing, curing, or other factors affecting the quality of the concrete.

Record Keeping

Record keeping is an important part of concrete inspection, as it provides a permanent record of the inspection results and helps to ensure that the structure remains safe and stable over time. Some key elements of concrete inspection record keeping include:

Inspection Details: The details of the inspection, including the date, time, location, inspector’s name, and a description of the inspection method, should be recorded in the inspection report.
Observed Deficiencies: Any deficiencies observed during the inspection should be recorded in the report, including details such as the location, size, type, and severity of the deficiency.
Recommendations: Any recommendations for repairs or reinforcements that are needed to address the deficiencies should be recorded in the report, along with the estimated cost of the repairs.
Photos and Drawings: Photos and drawings can be used to supplement the written record of the inspection and provide visual documentation of the deficiencies and recommendations.
Follow-Up: Any follow-up actions taken after the inspection should be recorded in the report, along with details of the date, time, and results of the follow-up.

By keeping accurate records of the concrete inspection, the inspector can provide a permanent record of the inspection results and help to ensure that the structure remains safe and stable over time. This information can also be used by future inspectors and decision-makers to evaluate the condition of the structure and make informed decisions about maintenance, repairs, and upgrades.