A Study on the Effects of Materials Finer than 88 μ Sieve in Mountain Sands on the Strength of Mortal

Abstract

This paper describes the results of a fundamental experiment on the effects of materials finer than 88 μ sieve in mountain sands on the strength of mortal. The mountain sands existing in Boso Peninsula contain considerable materials finer than 88 μ sieve. According to the results of our previous experiment, it seemed that they had some influences upon the mixes and strengths of mortal. It was difficult, however, to measure the accurate quantities of them. So we produced six kinds of fine aggregate by mixing them with the normal sands. (table 1) We considered several mixes and strengths of mortal composed of the fine aggregates described above. As the result, it seems that the effects of materials finer than 88 μ sieve are considerable. The results obtained are as follows; 1) In case of 60 percent of water-cement ratio, the materials finer than 88 μ sieve exert little influence on the mix and strength of mortal. 2) In case of less than 50 percent of water-cement ratio, the materials finer than 88 μ sieve have a remarkable influence upon the mix and strength of mortal. 3) In case of 2 percent of the materials finer than 88 μ sieve in the proportion of the fine aggregate, the materials exert little influence upon the mix and strength of mortal.