| Title |
Studies on the effects of Aggregates Characterics Upon the Behaviours of Hight Strength Concrete |
| Abstract |
The report presents the results of an experiental investigation on the compressire strength of concrete with particular reference on size and quantity of coarse aggregate. Several series of teats were carriced out using single-size aggregate which are in narrow range of size. It is shown that the large is pebble and the more aggregate is contained in concrete, the weaker is the concrete. When these relations are combined, the strength of one size aggregate concrete is expressed as a plane in space co-ordinate, with different pasition. according to the mortar strength which is mainly governed by water coment ratio. When the interface fond in ordinary concrete is the same with that of one size aggregate concrete, the compresive strenth of the former can be expressed with the strength of each on size aggregate concrete and with each aggregate contents in present concrete. It is shown that the concrete has its own strength compositions according to the quantity and the size of coarse aggregate. It was been reported previously by the author that at a given mortar the larger is the size and the greater the volume braction of gravel, the lower is the compressive strength in one size gravel concrete. And an interpretation was presented that the strength of one size gravel concrete can be represented in a plane debinded by the size and the volume fraction of gravel. The present report discusses the character of the strength plane with reference on consistency of concrete. The volume fractions of gravel in concrete and sand in mortar are taken up as the factors influencing the consistency of concrete. It is shown that the concrete strength of same consistency is represented as a line on the strength plane when the consistency is ajusted by the size and the volume fraction of gravel and that the strength plane can be assumed of to be constructed with these lines. Test resul shows that the large is the sand content in mortar, the smaller is the strength deduction of concrete from the mortar strength and the value of strength deduction is the same at any watercement ratio when mix proportion of cement paste, sand and graree is kept the same. Thus the sand content in mortar is though to play important role in strength of concrete as well as water cement ratio, the size and volume fraction of gravel. |