Mass Concrete Structures
Mass Concrete Structures - Related Videos
01:22
Mass Concreting
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2024
Mass concreting refers to the process of placing large volumes of concrete, such as in gravity dams. The heat generated during the cement hydration process and differential cooling rates within the concrete mass can lead to a temperature gradient, which can result in thermal cracks in the concrete mass. To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
10:00
Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures
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Cited by 38 •
2017
We propose a method to measure a parameter that is highly relevant for corrosion assessments or predictions of reinforced concrete structures, with the main advantage of permitting testing of samples from engineering structures. This ensures real conditions at the steel-concrete interface, which are crucial to avoid artifacts of laboratory-made samples.
11:23
Tests on Fresh Concrete
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2017
Source: Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA Concrete consists of two phases, a cement paste phase comprised of cement, water, and air, and an aggregate phase comprised of coarse and fine aggregates. There are two key considerations when designing a concrete mix. First, the concrete must be workable and easy to cast in the forms in its fresh condition, even when the forms are packed with steel reinforcement. In this condition, it is the...
08:08
Compression Tests on Hardened Concrete
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2023
Source: Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA There are two distinct stages in a construction project involving concrete. The first stage involves batching, transporting, and casting fresh concrete. At this stage, the material is viscous, and the workability and finishability are the key performance criteria. The second stage occurs when the hydration process begins shortly after the concrete is placed in the form, and the concrete will...
10:09
Tests of Hardened Concrete in Tension
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2023
Source: Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA In a previous laboratory focused on concrete in compression, we observed that concrete can withstand very large stresses under uniaxial compressive forces. However, the failures observed were not compressive failures but failures along shear planes where maximum tensile forces occur. Thus, it is important to understand the behavior of concrete in tension and particularly its maximum strength...
FAQs
Cement hydration releases heat inside the concrete, and the interior can become warmer than exposed surfaces. As the outer regions cool while the core remains hot, temperature differences create thermal gradients. These gradients generate tensile stresses when the concrete cannot deform freely. If the stresses exceed the material’s resistance, cracking may develop during the early stages of construction.
Temperature gradients matter because they connect internal heat generation with tensile stress and cracking risk. A large difference between the warmer interior and cooler surfaces can produce restraint within the element, particularly as temperatures change over time. Managing the gradient helps protect durability, watertightness, and structural performance in large or heavily reinforced concrete components.
Concrete mixture design is one of the main ways engineers manage heat generation in large-volume placements. The mixture must be selected with attention to the heat released during cement hydration and the resulting temperature change. By controlling this thermal behavior before placement, engineers can reduce conditions that contribute to early-age cracking and coordinate the mixture with other temperature-control measures.
Temperature monitoring shows how the concrete’s internal and exposed regions are responding during construction. Engineers can use these observations to identify temperature changes and gradients that may increase cracking risk. Monitoring also helps evaluate whether cooling, insulation, staged placement, or mixture-design measures are controlling the thermal conditions as intended, supporting timely decisions during construction.
Engineers combine several measures rather than relying on one control. Staged placement can manage the amount of concrete placed at a time, while cooling systems limit temperature rise and insulation moderates temperature change at exposed surfaces. Temperature monitoring provides feedback on these measures. Together with suitable mixture design, they help reduce thermal gradients and early-age cracking.
Applications include dams, bridge piers, thick foundations, retaining structures, and other heavily reinforced components. These elements may require careful thermal control because early-age cracks can affect durability, watertightness, and structural performance. Engineering practice therefore links construction planning, temperature management, and monitoring to the functional demands of each large concrete element.