Experimental Study Of Phase Change Materials In Mass Concrete

With the rapid development of global industry While the temperature crackinduced by cement hydration heat within the construction has been demonstrated to bethe most deleterious crack which would deteriorate the workability of buildings andservice life meanwhile great economic loss was caused. However at present theapproaches of temperature cracks controlling are focused on the materials technologyand construction measures such as raw materials selecting mix proportionoptimization of concrete pre cooling aggregates partitioned casting and coolingwater pipe Although these measures have reduced the maximum temperature rise inmass concrete to some extent but they have complex process need high cost andcann’t control temperature cracks in the concrete structure effectivelyPhase change material (PCM) has high latent heat and small temperature changein the phase change process Some cement hydration heat can be absorbed by PCMtherefore the inner temperature rise and temperature stress of concrete can be reducedin that the high energy storage density and small temperature change in the phasechange process of PCM It is a brand new method to reduce the temperature rise andminimize the temperature crack using PCM Focus on reducing the temperature rise ofmass concrete by PCM the preparation and application of PCM were thoroughlyinvestigated based on the characteristics and temperature history of mass concreteand the phase change properties of PCM The mainly research conclusion of thisthesis are list as follows1. The PCM big capsule preparation method was proposed The experimentsresults showed the temperature rise induced by hydration heat could be reduced in acertain extent with application of pre embedded PCM big capsule2. According to the experimental study of compressive strength of concretepre embedded different volume PCM big capsules The influence of PCM big capsuleon the strength of concrete is insignificant3. On the basis of theory studies the calculation method of PCM big capsuleconcrete adiabatic temperature rise was proposed Calculation analysis of pre embedded PCM big capsules in the concrete with different cement results in thatthe more cement in per unit volume of concrete the bigger temperature amplitude ofthe corresponding proportion of PCM on hydration heat4. According to law of cement hydration ordinary concrete internal temperaturechanges was analyzed adiabatic temperature rise model of phase change concrete wasestablished new ideas to control the temperature with phase change materials wasproposed in this paper The temperature field were calculated by ANSYS1Adiabatic temperature rise model of PCM big capsules concrete wasestablished temperature rising process was divided into three segments and thesimulation calculation formula of adiabatic temperature rise model was as follows2According to adiabatic temperature rise model of PCM big capsulesconcrete and calculation of ANSYS the design method of PCM big capsulespre embedded in different parts of concrete was put forward3The economic rationality of big capsule used in concrete is studied, and themeasures of cost controlling is proposed.