Roman secret to durable architecture? Self-healing concrete
- January 13, 2023
- Posted by: OptimizeIAS Team
- Category: DPN Topics
No Comments
Roman secret to durable architecture? Self-healing concrete
Subject: Science & Tech
Section :Msc
Roman architecture:
- For many years, researchers assumed the key to the ancient concrete’s durability was based on one ingredient: Pozzolanic material, such as volcanic ash from the area of Pozzuoli on the Bay of Naples.
Recent findings:
- Under closer examination, the researchers found the ancient samples also contain small, distinctive, millimetre-scale bright white mineral features, which have been long recognised as a ubiquitous component of Roman concretes.
- These white chunks often called “lime clasts,” originate from lime, another critical part of the ancient concrete mix.
- The relict lime casts were earlier thought of as evidence of sloppy mixing practices or poor-quality raw materials.
- On close examination, they found the Romans employed a hot mixing method and used quicklime in conjunction with, or instead of, slaked lime for producing concrete.
- Hot mixingwas actually the key to the super-durable nature.
What is Self healing concrete?
- It will biologically produce limestone to heal cracks that appear on the surface of concrete structures.
- Bacterial concrete or self healing concrete fills up the cracks developed in structures by the help of bacterial reaction (produce limestone) in the concrete after hardening.
Hot mixing process:
- During the hot mixing process, the lime clasts created a brittle structure with a reactive calcium source.
- The calcium would travel through the lime clasts, react with water and quickly fill any cracks.
Schematic of the proposed mechanism for self-healing within ancient Roman mortars
- The calcium-saturated solution could also react with pozzolanic materials to further strengthen the composite material.
- These reactions take place spontaneously and automatically heal the cracks before they spread.