Compressive strength 10 History of engineering and technology 9 Technology: general issues 9 Durability 6 Concretes 5 Portland cement 5 Pozzolanic materials 5 Cements 4 Ordinary Portland cement 4 Silica 4 Tensile strength 4 Cement 3 Materials science 3 Mechanical properties 3 Mixtures 3 Partial replacement 3 Pozzolanic properties 3 Aggregates 2 Alumina 2 Aluminum oxide 2 Bending strength 2 Cement replacement 2 Chlorine compounds 2 Concrete mixtures 2 Construction 2 Control samples 2 Corrosive effects 2 History of engineering & technology 2 Hydrated lime 2 Hydration 2