Abstract:According to the problem of relatively low strength and relatively high cost of high-water material

choosing fly ash and silica fume as two additives

the properties of modificated high water material was studied

and the additive content were 5%

10%

15% and 20%

respectively.The internal microstructure and macroscopic properties of high water material mixed with additives were studied using SEM scanning electric microscopy and computer-controlled electronic universal testing machine.Experimental results showed that additives had a great impact on properties and microstructure.The addition of 20% fly ash or 10% silica fume both could improve the compressive strength to 0.36 MPa and the strength was increased by 20% compared with pure high-water material.Besides

the residual strengths were improved effectively.The morphology

diameter and space mesh structure of high-water material were changed due to fly ash and silica fume addition.The crystal morphology of high water material mixed with fly ash were dominated by needle bar

and the number of large diameter crystal was increased

the crystal structure’s pore was filled with ball-shaped calcium silicate hydrate and residues.The branches morphology of material mixed with silica fume increased the connection of crystals and the compactness of mesh structure.It was proved that the compressive strength was determined by crystal morphology

diameter

lap of the crystal structure and the dense state of lattice structure.