An ideal structural model for very low porosity cementitious systems

An ideal structural model for very low-porosity cementitious materials is proposed. The model is based on energy, structural stability and durability criteria. It is suggested that the ideal structure consists of surface reactive fine fillers and cementitious products combined to form a chemically stable mature network with good interfacial bond. A new method involving treatment of aggregate surfaces has been investigated for use in forming ideal structures. Effects of matrix and filler characteristics on interfacial bond are discussed. A method of replacing a large quantity of unhydrated cement in very low porosity cementitious systems has been investigated. The experimental results demonstrate that interfacial bond is an important factor affecting mechanical properties; replacing unhydrated cement by inert fine aggregates results in a considerable decrease of strength. Surface treatment of aggregates was effective in maintaining the compressive strength of mortar at the same level as pure cement pastes. Surface hydraulic aggregates were effective in producing the ideal structure for very low porosity cementitious materials. It appears that a key factor in approaching ideal structure is changing inert aggregate surfaces into chemically reactive ones.