Research On Mix Proportion Design Of Basic Magnesium Sulfate Cement Concrete

Basic magnesium sulfate cement concrete is a new type of construction materials,which has high strength, high tensile properties, high toughness and corrosion resistance. There is no precedent at home and abroad. It is applied to large span bridges, urban light rail viaduct, tall and super-rise buildings to equip the structures with excellent durability and safety. Meanwhile, the size of cross section will be reduced, as a result, the weight will be reduced, as a result, the application of basic magnesium sulfate cement concrete is cost-effective. At the same time, the reduction of the dosage of concrete can help saving energy and reducing energy consumption, basic magnesium sulfate cement concrete will may be one of the main development direction of new building structure materials.According to the features of raw materials, this thesis studies the effect of raw materials and preparation parameters on basic magnesium sulfate cement concrete.This thesis establishes the specification of basic magnesium sulfate cement concrete. This thesis studies basic performance and compressive strength of basic magnesium sulfate cement concrete.The findings of the study can be concluded as the followings:(1)When the amount of the cement's dosage ranges from 13% to 51%, cement mortar strength and the dosage of admixture is a linear relationship; If the content is higher, the strength of cement is lower.(2)When the amount of the cement's dosage ranges from 530kg/m~3 to 630kg/m~3, if the dosage of cement is higher, the slump is larger, which means the workability of fresh concrete is better. However it has no effect on compressive strength of concrete. So a good amount of cement not only can obtain a good performance, but also a perfect economic benefit.(3)The concrete compressive strength of cement and cement/water ratio is a linear relationship, if cement/water ratio is higher, the concrete compressive strength of cement is larger; the slump and water/cement ratio is a linear relationship, if water/cement ratio is higher, the slump is higher.(4)At the same mix proportion, if the type and particle size of coarse aggregate is biger, the slump is higher. When making high strength concrete,the priority should be the coarse aggregate with low crush value and small particle.(5)The highest compressive strength of the basic magnesium sulfate cement concrete will be achieved when the sand ratio is 40%.(6)The best curing condition is that the temperature is 20±2 ? and the humidity RH60 %±5%, in which case the compressive strength of concrete is largest.(7)In the range of0%~33.3%, when the increase of the dosage of admixture, the concrete compressive strength and the slump will be decreased.(8)Naphthalene water reducer has a great influence on the performance ofbasic magnesium sulfate cement concrete and the water-reducing rate is high. If the dosage of water reducer is 2.5%, the water-reducing rate will be reached 32.4%. At the same slump, if the dosage of water reducer is 1.5%, the compressive strength of concrete will be largest.(9)According to the results of experimental study, we can obtain the chart of water consumption, the chart of sand coarse aggregate ratio, standard deviation, maximum water/cement ratio and minimum cement content.(10)According to the experiment, we can find that the absolute deviation between actual results and theoretical data is less than 4%.