Development And Engineering Application Of Super Early Strength Cement Stabilized Repair Materials

The cement stable base is the main form of the base structure of the high grade highway in China.In the construction or maintenance process of cement stabilized materials as a base,the formation of its strength is a "bottleneck" process that affects the progress of the whole project and restricts the construction period.Because before the early strength of the base layer is formed,if the surface layer is paved,it will bring hidden trouble to the project,leading to the quality problems such as loose base layer and insufficient strength.At present,the traditional cement stable material is used for a long time,so the construction period can only be extended or the construction surface of the base can be increased to wait for the base to form enough strength,which has a great impact on the society and economy for the maintenance and transformation of the road section with tight construction period requirements,large traffic volume and high social attention.Based on the research results at home and abroad,combined with the characteristics of cement stabilized base material and its construction environment requirements,through laboratory tests and engineering applications,under the conditions of high temperature,normal temperature and low temperature,respectively,to develop composite material composition formula that meets the requirements.In addition,the mixing ratio design of cement stabilized macadam was carried out to verify the performance of unconfined compressive strength,indirect tensile strength,compressive resilience modulus,dry shrinkage and warm shrinkage test,and to determine the performance index meeting the requirements of the specification.Through site construction and technical inspection,reasonable construction technology and maintenance measures are put forward.A new type of cement stabilizing material for the base course is developed.The main research results are as follows:(1)according to the choice of 18 kinds of inorganic and organic composite materials formula,# 1-8(Naphthalene series water reducing agent: calcium formate:calcium acetate / 20:1:36)and 2-8(Naphthalene series water reducing agent: calcium formate: sodium sulfate / 20:1:36)material after 1.5 d compound stabilized macadam can achieve average 85% of the 28 d strength of the cement stable macadam mixture,can undertake surface,select 1-8 and 2-8 compound admixtures as a regular environment early strength under the condition of maintenance materials;2-9(Naphthalene series water reducing agent: calcium formate: sodium sulfate/ 20:1:40)composite cement stabilized gravel 2d can achieve the 28 d strength of ordinary cement stabilized gravel 100%,can be used for surface construction in low temperature environment,2-9 composite admixture materials;At high temperature,the test strength of 1-1(Naphthalene series water reducing agent: calcium formate: calcium acetate/12:1:30)material is higher than that of ordinary cement stabilized macadam(16h)than that of ordinary cement stabilized macadam(28d).Therefore,surface construction can be carried out.(2)through laboratory test research and engineering application,the new material developed is fast in the early stage of condensation and hardening,fast in the early stage of strength rise,and continuous development in the late stage of strength,and various performance indicators can be higher than the standard value.This study solves the sharp contradiction between the long construction time and the rapid development of the early strength of cement stabilized base material,and has a broad application prospect.