Abstract
Gypsum is often used with some aggregates as in the case of Normal Portland Cement, while it is used without aggregates because its length change is quite little under dry condition. To use Gypsum in the form of particle reinforced composite materials, it is necessary to find suitable aggregates and appropreate mixings. Then some experiments were carried out to examine the properties of particle reinforced composite materials using Gypsum as the matrix phase and several convensional aggregates as the dispersed phase. In this paper the experimental results and some considerations are explained and concluded as follows. For the matrix phase in particle reinforced composite materials, II-anhydrite, α-hemihydrate and β-calcium sulfate hemihydrate are possible to be used. Among these three, II-anhydrite is best because of the strength and the easiness to adjust the workability of the mixture. For the dispersed phase a kind of artificial light weight aggregate is found to be suitable to reinforce Gypsum matrix. By the particle reinforcement using this artificial light weight aggregate, the young's modulus, the tensile strength, the toughness and the creep rate are improved. Especialy the decrease rate of the compressive strength and the young's modulus of cast Gypsum absorbing water are turned into little.
