Online-testing Technology Of Moisture Of Sand For Cement Concrete Mixing Equipment

The precise measurement of the moisture of the sand is very important in the progress of the concrete’s production. Traditional drying method belongs to the offline-testing mode,which stretches out for a long time,and the testing sample is often not representative enough. Improved moisture online-testing method can detect the number of the moisture real-time, and the test frequency is high, the representation is strong, the accuracy is high, and the deviation is low. One great improvement of technology is the change of traditional drying method to online-testing of the moisture. It improves the instantaneity of water detection,which finally improves the Mix proportions of concretes.There are various kinds of principles for moisture testing, but the main approaches are Resistance method、Capacitance method、Neutron method、Infrared method and Microwave method. As for Resistance method, the resistance of the sand is actually too high for the sensor to receive testing signal(in terms of voltage), which may pull in external interference signal, so it’s not suitable for online-testing. However, the remained four principles are all good for it. Besides,by researching the physical and chemical properties of sand, and the progress of storing and transporting, we put forward some influencing factors of the online-testing of moisture. According to detailed research of the principles and influencing factors, the microwave method is chosen to achieve this online-testing technology. Then we purchase a piece of equipment to research this technology on that basis, including its advantages, feasibility, accuracy and reliability.Even though the technique of moisture online-testing has many advantages above, it is still restricted by few factors. So we design few experiments to verify the influence of these factors. In this article, we analysis the feasibility of this online-testing technology theoretically, and design some comparative experiments to research this technology. Finally, the feasibility, reliability and accuracy of this online-testing technology are proofed by processing and analyzing the experimental data.In order to show the superiority of this online-testing technique to traditional drying method, we designed an extra comparative test to highlight this superiority. By changing the angle of the sensor, the best position of the sensor is figured out to be 45 degree. Other experiments eliminates some factors that may influence the result of measurement. The experiments finally reach the target that the online-testing technique of moisture is suitable enough for concrete production, and it is reliable too. These conclusions will bring instructive significance for concrete’s production.