It has been an evolution through the “dry set masonry” (setting stones within horizontal rows) since the human began sculpting stones. On the Roman empire, the concrete reaches its maximum splendor until the XIX century.
It should be noted John Smeaton, an engineer of the XIX century; After the collapse of some lighthouses due to the force of the water, he fitted the stones with a mix with quicklime, clay, sand and iron slag, i.e. concrete. From this material he built the Eddystone lighthouse (England).
Concrete is one of the materials most used in construction. It is formed from mixture aggregates with hydraulic conglomerates (the most common is the cement). The main advantages are:
1. Resistance: Comparing to other materials such as wood and brick.
2. Adaptability: The concrete can adopt a variety of forms.
3. Soundproofing: It behaves as a good insulating material.
4. Economical: Is a durable material. Low cost maintenance.
Although concrete works well at compression, it does not do it at traction. So it is necessary mix it with other easy traction material. The reinforcement (active and passive) absorbs the traction effort. So,which are the main characteristics that concrete has to achieve in any project?
- Fresh concrete
– Docility: it has to be enough to avoid hollows concrete. This value is provided by its consistency where the water has a primary role.
– Density: the minimum value must be 4 times the size of the top aggregate.
– Plastic shrinkage: this os due to the water evaporation. However some factors can help: additives to reduce the contraction, optimized mixture and avoiding water losses.
- Hard concrete
– Compactness: the higher the value, the less the porosity.
– Retraction: controlled by the retracting and expanding joints.
– Fluency: different deformations in the structure that continues over time.
We highlight the most common concrete combinations.
1. Glass: it brings lightness allowing the natural light. Guanghhou Opera, China (Zaha Hadid).
2. Wood: it provides warmth. The Nishi building, Australia (Molonglo Group).
3. Metal: it emphasizes the concrete and provides brightness. Linked Hybrid complex, Pekin (Steven Holl).
4. Lighting: it emphasizes the sculpture. Capilla del atardecer, Acapulco. México. (BNKR Arquitectura).
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