3. Conclusions. Trends and prospects

The perceptible evolutions are of very different natures, but they reflect notable changes in construction methods affecting the design of structures, the organization of building sites, the work of the mason himself and, more globally, the relationships between the various participants in the construction industry as a whole.

Here are a few examples to illustrate our point.

• In the case of hollow concrete blocks, wall thicknesses have been progressively and noticeably reduced, in order to reduce unit weight or increase dimensions (height, for example) without changing the weight of the product. The corresponding masonries now have a markedly brittle mechanical behaviour, which is similar to that of hollow terracotta products, which have long included largely honeycombed products with very thin walls.