The researchers studied how using recycled concrete affects its strength and properties compared to regular concrete. They broke down old concrete, mixed it with cement, and tested different mixtures with varying amounts of recycled concrete. They found that while the strength and stiffness of recycled concrete decrease, its physical properties can be improved. By using up to 40% recycled concrete, high strength can still be achieved. This means that construction waste can be used to make recycled concrete that performs well in construction projects.