| The adsorption properties of activated carbon with different particle sizes at different temperatures and different adsorption modes and the encapsulation effects of different proportions of epoxy resin were studied.Phase change energy storage aggregate(PCESA)was prepared by adsorption of phase change material(PCM)tannic acid octanoic acid with activated carbon.The phase change characteristics of PCM and PCESA were tested by DSC,and the microstructure of the adsorbed material was analyzed by SEM image.The adsorption performance of activated carbon was analyzed by PCM soak adsorption rate at different temperatures,and the PCM adsorption performance test under ultrasonic adsorption and vacuum adsorption was carried out.The experimental results show that the phase transition characteristics of PCM and PCESA are stable and have good thermal physical properties;the pore structure of activated carbon with 6mm particle size is relatively good,and the performance of adsorbing PCM is better;at 30?,40? and 50? water bath temperature The adsorption rate is higher;the vacuum adsorption performance is better than other adsorption methods;the epoxy resin,diluent and curing agent are better in the ratio of 1:0.15:0.25.The phase change energy storage aggregate was prepared by adsorbing citric acid octanoic acid with activated carbon as the matrix material.With different dosages of activated carbon aggregates,activated carbon energy storage aggregate and fly ash were used to study the compressive,tensile and flexural properties of concrete.The influence of different dosages of silicon powder on the compressive and tensile properties of activated carbon energy storage aggregate and fly ash double concrete.The test results show that the incorporation of activated carbon aggregate and fly ash will reduce the strength of concrete.When single-doped 10%activated carbon aggregate,single-mixed 15%fly ash,double-doped 10%activated carbon aggregate and 15%fly ash,the compressive strength loss rate is 26.50%,25.42%and 38.09%respectively,the tensile strength loss rate is 16.19%,13.65%and 28.25%respectively,the flexural strength loss rate is 28.54%,15.73%and 33.51%respectively;when the activated carbon energy storage concrete is mixed with 10%silicon powder,the concrete compressive strength and tensile strength are increased by 16%and 10%respectively.The cube compression and splitting tensile tests were carried out on the concrete specimens with different admixtures after 3d,7d,28d,56d and 90d.The results show that the compressive strength of single-silica-silver concrete is higher than that of other mixed phase-change concrete except 3d age.The single-mixed fly ash will further reduce the strength of phase-change concrete,the strength of the reference phase change concrete can be achieved double-mixed fly ash and silicon powder at 90d age.The 7d compressive strength of single-doped silicon powder phase-change concrete increased rapidly with a growth rate of 85.35%.The tensile strength of 56d increased rapidly with a growth rate of 43.66%.The 7d compressive strength of single-added fly ash phase-change concrete increased rapidly with a growth rate of 59.31%.The tensile strength of 28d grows fast,and the growth rate is 54.94%.The 28d compressive strength of double-doped silicon powder and fly ash phase change concrete grows faster with a growth rate of 62.75%,56d tensile strength grows faster with a growth rate of 59.14%.The growth rate of compressive strength of 7d and 28d of single-silica powder phase change concrete was 26.04%and 17.08%respectively higher than that of single fly ash.The growth rate of compressive strength of 56d and 90d of single fly ash phase change concrete was 26.04%and 17.08%respectively higher than that of single-silica powder.To observe the different interface microstructures of phase-change concrete at different ages(3d,7d,28d,56d and 90d),the specimens after the fracture were cut and sampled,and the internal micro-morphology of the concrete specimens with different admixtures was observed by scanning electron microscopy.The results show that with the increase of age,the interfacial transition zones of different admixtures have different degrees of development.At 7d and 28d,the ash hydration reaction is relatively slow,while the silicon hydration reaction is relatively.It is faster and has a certain filling effect on the micro cracks in the early stage;the effect of double-filled fly ash and silicon powder on the internal pore filling of concrete is better than that of single-filled fly ash and single-doped silicon powder.In order to study the mass loss,appearance and mechanical properties of phase change energy storage concrete under different phase change cycles,and the effects of different admixtures on the frost resistance of phase change concrete,seven different numbers of concrete specimens were designed.The results show that under the same number of cycles:the compressive and tensile strength decreases with the increase of the amount of phase change energy storage aggregate.And the double-filled fly ash and silica powder group had less compressive and tensile strength loss than the single-mixed fly ash group and the single-doped silicon powder group.Among them,the compressive strength loss of the single fly ash group was the largest,and the 100 phase change cycle decreased by 24.58%.Among them,the tensile strength loss of the single-added fly ash group and the single-doped silicon powder group was 27.64%,and 30.31%after 100 times of phase change cycle.At last the relationship between the factors affecting the thermal conductivity of phase-change concrete and the type of aggregate and its volume fraction and the type of admixture were studied.The results show that the thermal conductivity of concrete in the ordinary group and the activated carbon group fluctuates less.With the increase of the amount of activated carbon energy storage aggregate,the growth rate of thermal conductivity increases obviously and increases almost linearly.The thermal conductivity of single fly ash is obviously higher than undoped group.But it is worse than the single-doped silicon powder group.The thermal conductivity of the double-mixed fly ash and silicon powder is slightly higher than that of the single-doped fly ash group.Figure 43 table 20 references 67... |
PDF Full Text Request