Related Concept Videos

What is Weather?01:07

What is Weather?

Overview
Global Climate Change01:50

Global Climate Change

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
Stress: General Loading Conditions01:15

Stress: General Loading Conditions

To grasp the intricacy of real-world conditions where multiple loads are applied simultaneously to a structure, one might visualize a section passing through a specific point within a body, aligned parallel to the xy plane. This section is subjected to various forces, including original loads, normal forces, and shearing forces.
The shearing force, possessing potential directionality within the plane of the section, is simplified into two component forces running parallel to the x and y axes.
Masonry in Cold and Hot Weather Conditions01:21

Masonry in Cold and Hot Weather Conditions

In cold weather, masonry construction requires specific precautions to ensure mortar does not freeze before curing, as this can significantly weaken its strength and watertightness. Mortar temperature should be maintained between 60°F and 80°F to support proper hydration and curing. Below 40°F, mortar water must be heated, but should not exceed 120°F as high temperatures can reduce mortar's compressive and bond strength.
Other key practices include keeping masonry units and sand dry and...
Hot Weather Concreting01:20

Hot Weather Concreting

Concreting at elevated temperatures accelerates the hydration process, leading to quicker setting but potentially reducing the long-term strength of the concrete structure. Additionally, low air humidity fosters rapid moisture loss from the concrete, resulting in reduced workability, pronounced plastic shrinkage, and a higher likelihood of crazing.
Mitigating the heat increase in concrete can be economically achieved by shading aggregate stockpiles to prevent heating from solar radiation,...
Cold Weather Concreting01:27

Cold Weather Concreting

When freshly poured concrete is exposed to freezing temperatures before it has set, the water within the concrete can freeze. This expansion disrupts the setting process, delays chemical reactions necessary for hardening, and increases the volume of pores within the hardened concrete, which weakens its overall structure. If the concrete manages to reach an appreciable strength before it freezes, the damage can be somewhat mitigated.
To counteract the negative impacts of cold weather, ensuring...