Roman concrete was remarkable because it could last for thousands of years, even underwater. Its mixture of lime, volcanic ash, and water allowed it to develop cracks that didn’t weaken it. When water entered a crack, it reacted with the lime to form calcium carbonate, which gradually filled the crack and bonded the concrete back together, essentially giving it a natural self-healing ability.
It is official! President Trump has officially withdrawn the United States from the World Health Organization Promises Made. Promises KEPT.
Enjoyed the video?
Help us improve! Leave feedback on your experience.
0
0 Komentar