The 1st field trial of Semi-flexible pavement has been completed successfully by using STP, cement milk modifier, provided by TAIYU Kensetsu Co., Ltd. on Vo Chi Cong street, Da Nang on 11st September, 2017. This field trial using STP has been applied to prevent severe rutting problem on heavy traffic roads.
≪Properties of Open-Graded asphalt mix “BTNR12.5”≫
The mix proportion of Open-graded asphalt mix used for Semi-flexible pavement is very important because it would become the matrix or skeleton of the pavement. Especially, air void percentage and connected air void percentage need to be determined carefully because permeability of cement milk depends upon them. So, tentative three (3) mix proportions are set and tested, based on those test results, optimum mix proportion has been determined. The thickness of the Semi-Flexible pavement for this site is very thick, 10 cm.
Therefore, the air void percentage of the Open-Graded asphalt mix has been set to be a little larger, like about 27%. Furthermore, hot bin No.2 was not used in order to enlarge the connected air void percentage.
≪Production of Cement Milk using STP≫
Portland cement “PCB40”, “STP” provided from TAIYU Kensetsu Co., Ltd., and water are employed for the cement milk. “STP” is a modifier to give cement milk flexibility and toughness. And, they are mixed at construction site. Each materials are added into a drum can and mixed in the order of water, cement, and STP.
≪Injection of cement milk & completed Semi-flexible pavement≫
Controlling the amount of cement milk injected, injection work has been completed. Even though the thickness is 10cm, cement milk has been perfectly injected by controlling the viscosity and using vibration roller.
Link to use PDF data