The second edition of the book mentioned in the link above was completed today. Now that the chapters have been delivered to Elsevier, it only remains for that publisher to take care of the remaining steps for this new edition to be published within a few months.
Although there are many people who have no idea that concrete is the most used material on Planet Earth, the fact is that there are many infrastructures built with that material that degrade prematurely (for various reasons that go beyond the scope of this post ) necessitating repair (and/or rehabilitation) works that constitute the scope of the referred book. When these works do not happen, the result is the one seen in Italy with the collapse of the Morandi bridge, which killed 43 people https://www.theguardian.com/cities/2019/feb/26/what-caused-the-genoa-morandi-bridge-collapse-and-the-end-of-an-italian-national-myth
However, the most interesting part of this post concerns the question I asked ChatGPT: "I want to know the composition of a concrete, based on recycled aggregates, with a compressive strength of 100 MPa, after 28 curing days, which will be subject during these 28 days to a temperature of minus 2 degrees celsius and exposed to chemically aggressive conditions, will have a useful life of 1000 years"
I reproduce the ChatGPT answer below, highlighting the part in yellow color, which shows that the area of civil engineering is (still) safe from the brute force of the aforementioned model of artificial intelligence, which is already wreaking havoc in many other areas.
Answer of ChatGPT: To obtain a concrete with a compressive strength of 100 MPa, using recycled aggregates and with a durability of 1000 years, it is necessary to carefully consider the selection of materials and the formulation of the mix. Here is a composition suggestion:
- Cement: Use a high-strength cement such as grade 52.5 Portland cement or a cement with pozzolanic additions such as fly ash or silica fume. These types of cement are known to provide superior strength.
- Aggregates: Use high quality, durable recycled aggregates that are resistant to aggressive chemical conditions. Make sure that recycled aggregates are well processed, clean and free of impurities that could impair the durability of the concrete.
- Water-cement ratio: To achieve high compressive strength, it is recommended to use a low water-cement ratio, normally between 0.25 and 0.35. This proportion will reduce the porosity and improve the strength of the concrete.
- Additives: Add additives that improve the chemical resistance and durability of the concrete. For example, high strength plasticizer additives, permeability reducing additives and waterproofing additives can be used to increase durability and resistance to aggressive chemical conditions.
- Curing: Proper curing is essential to maximize the strength and durability of the concrete. Be sure to follow an appropriate curing regimen considering the -2 degrees Celsius temperature. This may include the use of thermal insulation and coatings to protect the concrete from freezing during the curing period.
Importantly, achieving a compressive strength of 100 MPa and a service life of 1000 years is a significant challenge. Therefore, it is recommended to consult concrete specialists, civil engineers and carry out laboratory tests to optimize the composition and guarantee the desired durability.
