Influence from Straw on Performance of Cement Insulation Mortar Using Mud from Washing Manufactured Sand

Insulation mortar was prepared with cement, mud from washing manufactured sand, wheat straw, vitrified microbead, polypropylene fibre and chemical admixture. Influence law of wheat straw on performance of cement insulation mortar was discussed. Influence factors included pretreatment method, dosage and length of straw. Features of straw surface pretreated by NaOH solution and bonding interface were observed by scanning electron microscopy. Dry density, compressive strength, thermal conductivity coefficient reduce with the increase of straw length and the decrease of soak time. When straw dosage increases, they decrease firstly, increase later. Straw reduces the mass loss of cement insulation mortar treated at temperature below 500℃. Straw surface pretreated by NaOH solution becomes rough. There are trenches with widths about a few microns. It makes a better interface combination between straw and cement matrix.