Aggregate Cooling
Aggregate Cooling - Related Videos
02:44
Heating and Cooling Curves
0 Views •
2020
When a substance—isolated from its environment—is subjected to heat changes, corresponding changes in temperature and phase of the substance is observed; this is graphically represented by heating and cooling curves. For instance, the addition of heat raises the temperature of a solid; the amount of heat absorbed depends on the heat capacity of the solid (q = mcsolidΔT). According to thermochemistry, the relation between the amount of heat absorbed or released by a substance, q, and its...
10:10
Aggregates for Concrete and Asphaltic Mixes
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2023
Source: Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA Concrete and asphalt are by far the most common construction materials used today. Concrete is a composite material consisting of cement, water, air, coarse aggregate, and fine aggregates. Fine aggregates are typically sands and coarse aggregates are natural or crushed rocks. Chemical admixtures to modify certain specific properties are also commonly used (i.e., superplasticizers to make the...
04:49
Technique for Intranasal Administration of α-Synuclein Aggregates
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2024
The present protocol describes a method for intranasal administration of α-synuclein aggregates. This method provides insights into α-synuclein propagation from the olfactory mucosa to the olfactory bulb in Parkinson's disease.
09:14
Tracking Hypoxic Signaling within Encapsulated Cell Aggregates
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Cited by 10 •
2011
A method for photo-encapsulation of cells in a crosslinked PEG hydrogel is described. Hypoxic signaling within encapsulated murine insulinoma (MIN6) aggregates is tracked using a fluorescent marker system. This system allows serial examination of cells within a hydrogel scaffold and correlation of hypoxic signaling with changes in cell phenotype.
08:23
Assembly and Operation of a Cooling Stage to Immobilize C. elegans on Their Culture Plates
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2023
This paper describes protocols for constructing and operating a cooling stage to immobilize C. elegans on their original cultivation plates en masse.
FAQs
Aggregates carry stored heat into the concrete mixture, so their temperature directly contributes to the temperature reached during mixing and placement. Cooling both coarse and fine fractions reduces this heat contribution before incorporation. This gives engineers greater control over fresh-mixture temperature and helps limit temperature-related effects during subsequent curing.
Aggregate cooling must balance heat removal with moisture control. Water spraying and evaporative cooling can lower temperature, but the aggregate must remain in a condition suitable for concrete production. Maintaining appropriate moisture conditions helps the cooled material function as intended in the mixture rather than introducing an uncontrolled change during incorporation.
These approaches remove or limit stored heat through different heat-transfer mechanisms. Shading reduces exposure to heat, while water spraying applies water to the aggregate, and evaporative cooling relies on heat removal associated with evaporation. Engineers can consider the available method and the required moisture condition when selecting an approach for hot-weather construction.
Temperature control begins before placement because heat already stored in the aggregates enters the fresh concrete during mixing. Lowering that initial contribution can reduce excessive temperatures through mixing, placement, and curing. This matters because controlling the thermal condition of the mixture supports workability and reduces the risk of temperature-related cracking.
A practical workflow is to identify the need for temperature control, select a suitable heat-transfer approach, cool the coarse and fine aggregates, and maintain suitable moisture conditions before incorporation into concrete. The cooled materials are then used during mixing, placement, and curing to help keep the fresh mixture within its intended thermal and handling conditions.
Engineers use this approach particularly during hot-weather construction, when aggregate heat can contribute to excessive concrete temperatures. Cooling may be applied before the aggregates enter the mixture so temperature control begins at the material stage. The resulting control can help preserve workability during handling and support the intended performance and durability of concrete structures.