Researchers at the Brunel University London have created a mix that can be added to concrete to protect it from the harms of the salt sprinkled on streets and pavements during the winter in Europe and many other countries.
Every year, specializing cars spread the salt, known as sodium chloride, in vast quantities on roads and pavements to stop them freezing. Water usually freezes at 0C, but when salt is added, the freezing temperature drops below this level, and the salt prevents water particles from creating solid ice crystals.
Most of this salt is ultimately washed away, but large quantities are absorbed as salty water, which causes the concrete to deteriorate and steel within to rust and corrode.
In the study recently published in the JOM journal, the researcher team led by the Jordanian Mazen Al-Kheetan, from the Brunel's department of Civil and Environmental Engineering, announced it has devised a new concrete mix -mainly composed of sodium acetate compound- that absorbs 64% less water and 90% less salt than normal concrete. It's hoped the new mix could lead to pavements that are best placed to withstand their annual dousing of salt.
"Incorporation of a sodium acetate compound into concrete, at the mixing stage, works on absorbing some of the water to form crystals that line the walls of the pores in the concrete. These crystals increase the hydrophobicity of the concrete (the amount concrete repels the water), which ensures the reduction of water uptake through the pores. Also, when applying de-icing salt to pavements made from this concrete mix, the presence of the protective compound within the pores work on fending off the water and the waterborne chlorides," Al-Kheetan told Asharq Al-Awsat via email.
"During our three-year study, we added different quantities of the sodium acetate compound to different concrete mixes, until we achieved the perfect mix providing these benefits," he added.
According to Kheetan, the new concrete mix still needs more long term tests in cold and warm weathers, before it becomes available for the industrial use, noting that "we still need two to three years of experiments before we can use the new mix on the roads."
Speaking about the possibility of using this concrete mix in regions other than Europe, Dr. Moujib Rahman, co-author of the study, told Asharq Al-Awsat: "This concrete can be used in the making of bridges, pavements, highways, houses, ports, and infrastructures or any surface that usually sees heavy rainfalls or salt precipitations."