Study On The Compressive Strength Of Cement Mortar By Pre-hydration Method

The concrete with ordinary Portland cement as a cementitious material is the most widely used building material in the world,which is 70% of the total amount of building materials.Under the development of modern science and technology,in order to better maximize the characteristics of cement,more and more scientific researches on cement materials,such as compressive strength,have been made.In this study,a very small amount of concrete pre-hydration is proposed.The compression strength of concrete is enhanced by the method of pre-hydration.The prehydration method uses a magnetic stirrer to hydrate a few cement.The pre-hydration cement paste is added to the mortar mixer with the remaining cement.It can make the hydration reaction better and faster.The experimental variables of this study are:cement content,pre-hydration time,machine speed and pre-hydration temperature.It is the effect of these four aspects on the compressive strength of cement.The principle of strengthening the compressive strength of cement pre-hydration by means of micro-analysis is introduced.The results of the study show the following:(1)The pre-hydration method can obviously improve the compressive strength of cement mortar in the early stage.(2)When the pre-hydration temperature variable is changed,the strength of the block will increase with the increase of the temperature.The intensity increases fastest on the third day.When the time variable of hydration changes: the strength of the block increases with the increase of the pre-hydration time at the same condition.The intensity increases fastest on the seventh day.(3)The test method of this experiment is orthogonal method.The optimum formula ratio of this test is 2% cement content,7.5h pre-hydration time,2000 rpm machine speed and 30 ℃ pre-hydration temperature.(4)The theoretical basis of the effect of pre-hydration method on the compressive strength of pure water slurry is analyzed.The theory is as follows:nucleation、hydration of cement、nanoparticles produced by pre-hydration、micro defect reduction、changes of hydration products and so on.(5)Through the analysis of the microstructure and the hydration heat,the pre hydration method can lead to the production of the hydrated product in advance,but itdoes not increase the amount of the product,so it is proved that the compressive strength of the specimen can be enhanced in the early stage.To sum up,the cement mortar is prepared by the pre-hydration method,and the early compressive strength of the concrete block is greatly improved.