Low Temperature Coarse Aggregate In Concrete Technology And Property Test Research

To explore the methods to reduce internal defects of concrete technology,to increase the compactness of concrete,reduce the porosity,reduce the number of all kinds of original crack,to reduce the early concrete shrinkage,don't increase too much cost.Concrete with low temperature coarse aggregate,reduce the number and size of early cracks in concrete,minimize the internal defects of concrete.Comparison test of concrete in normal temperature and low temperature by using ordinary gravel coarse aggregate,mainly has carried on the concrete compressive strength?splitting tensile strength?electrical properties of early concrete penetration resistance?ultrasonic probe test?Experimental study on one dimensional stress measurement in the early stage of concrete.The data were analyzed by chart analysis,curve analysis,mathematical statistics and so on,It is found that the experimental data has a certain statistical regularity,there is a close relationship between the internal variation of concrete and its technical characteristics.After analysis and summary,through the contrast experimental study on the following conclusions:1.Compared with common preparation of C40 concrete coarse aggregate,Low temperature coarse aggregate preparation of C40 concrete 28 day compressive strength increased by 7%---25%,growth effect is more obvious;2.Compared with common preparation of C40 concrete coarse aggregate,the tensile strength of C40 concrete prepared by low temperature coarse aggregate increased by 28 days 3%-8%;3.Low temperature coarse aggregate of C40 concrete 28 freeze-thaw cycle times higher than the normal temperature of 27 times;4.Low temperature coarse aggregate preparation of C40 concrete 28 days average sound speed of 3.560km/s,the sound of 42.2?s,ordinary C40 sound speed of 3.440km/s,sound 44.8?s;5.Low temperature coarse aggregate preparation of C40 concrete 28 days the average value of resistance 490?,class inductance 1.5mH,class capacitance 13.6 ?F;Compared with ordinary coarse aggregate mixture of C40 concrete class average 7.2% lower resistivity,Class inductance increased by 15.4%,class capacity decreased by 12.3%;6.Low temperature coarse aggregate preparation of C40 concrete early shrinkage pressure is 0.49196 N,compared with the ordinary coarse aggregate,the C40 concrete has increased by 287.3% compared with the early age,the late low temperature and room temperature internal stress shows 0.The experiment proved that low-temperature concrete technology properties of coarse aggregate preparation has a lot to improve,have great practical value in engineering practice.