0 Introduction Rubber powder polystyrene granule external wall insulation system is a building exterior wall thermal insulation system which has developed rapidly in recent years. The system has better solved the heat preservation, heat insulation, crack resistance, wind pressure resistance, earthquake resistance, fire resistance and 憎Water, weathering, and ventilation are a new type of energy-saving exterior insulation technology system. In this system, the thermal insulation layer composed of rubber powder polystyrene granule insulation slurry bears most of the thermal insulation performance of the whole system. In terms of durability, it is also a weak link in the whole insulation system. Therefore, the rubber powder poly benzene particles The performance of the thermal insulation slurry is critical to the overall thermal insulation system performance. Research and development of low-density, low thermal conductivity, high tensile strength and high water resistance of high-performance rubber powder polystyrene granule insulation slurry (hereinafter referred to as insulation material), analysis of its deformation behavior under warm conditions is extremely important.

It is necessary to conduct crack resistance research on the exterior insulation system of rubber polystyrene particles.

1 Composition of thermal insulation slurry 1.1 Selection of raw materials The screening and optimization of raw material ratio is an important step to achieve high performance of thermal insulation slurry. The thermal insulation slurry is composed of rubber powder and foamed polystyrene particles, and the volume ratio of the latter is not less than 80% of the thermal insulation mortar. The rubber powder is an inorganic cementitious material and various admixtures are premixed in the factory. The composite cementitious material prepared by the mixing technology generally comprises an admixture of cement, redispersible rubber powder, fly ash, quicklime, fiber, water reducing agent, air entraining agent, cellulose and the like. In this study, in order to simplify the research, the rubber powder is divided into the following parts: inorganic cementitious materials include cement, fly ash, quicklime, etc.; redispersible rubber powder refers to high molecular weight polymer; admixture includes Water reducing agent, air entraining agent, cellulose, etc.; fiber is used to increase the tensile strength of the thermal insulation slurry.

1.2 Relationship between compressive strength and dry density of test The thermal conductivity of thermal insulation slurry is directly related to its dry apparent density. According to the data provided by Beijing Zhenli High-tech Co., Ltd., the dry density is ensured under the premise of ensuring the compactness of the slurry. The smaller the thermal conductivity, the lower (see 圄1). According to this conclusion, in the experiment, we achieved the purpose of reducing the thermal conductivity by reducing the dry density of the thermal insulation slurry.

The test found that the compressive strength of the thermal insulation slurry is also substantially linearly proportional to its dry apparent density as shown in 圄2. Therefore, in order to reduce the thermal conductivity of the thermal insulation slurry and to ensure the basic compressive strength requirements, the contradiction between the compressive strength and the dry density of the thermal insulation slurry should be solved first.

The relationship between the compressive strength of the thermal insulation slurry and the dry density generally reduces the dry apparent density by two methods, one is to increase the volume of the polystyrene particles, and the other is to reduce the density of the powder of the constituent slurry. However, it has been found in the experiment that if the volume ratio of the polyphenylene particles is simply increased, the compactness of the thermal insulation slurry is lowered to make the loose workability directly affect the compressive strength of the thermal insulation slurry. Therefore, we reduce the density of the powder by changing the composition of the inorganic cementitious material in the rubber powder and supplement the various additives to increase the amount of the slurry in the thermal slurry to achieve the purpose of improving the compactness of the slurry.

The compressive strength of the required thermal insulation slurry is much lower than the strength of the rubber powder slurry after hardening, and the destruction of the material is generally caused by the weakness of the material (such as the interface), so there is no need to excessively require the rubber powder slurry. The hardening strength of the body. In the test, the amount of cement in the rubber powder is appropriately reduced, and a large amount of materials such as fly ash and lime which have a low density and can provide the working property of the thermal insulation slurry and the strength increase in the later stage are provided. Further, the density and uniformity of the thermal insulation slurry are further improved by adding an additive such as a water reducing agent and an air entraining agent and improving the stirring process. In this way, on the basis of reducing the density of the thermal insulation slurry, the compactness and compressive strength of the thermal insulation slurry are ensured and the compressive strength is improved.

36-The relationship between the strength of new building materials and the type and amount of redispersible rubber powder. Insulation slurry contains both inorganic materials such as cement, fly ash and polyphenylene granules. The organic materials should be organically combined. The role of the redispersible rubber powder is required. H. It is generally believed that the redispersible rubber powder forms a polymer between the inorganic cementitious material particles and between the cementitious material and the aggregate (polyphenylene particles) during the hardening of the slurry. When the redispersible rubber powder reaches a certain amount, the formed polymer film forms a spatial network structure inside the thermal insulation slurry, and the organic material portion and the inorganic material portion in the slurry are well cemented. Therefore, the choice and amount of redispersible rubber powder have an important influence on the compressive strength and tensile strength of the thermal insulation slurry.

Factors Affecting the Softening Coefficient In order to further improve the workability of the thermal insulation slurry and to increase the tensile strength of the thermal insulation slurry, a certain amount of cellulose is added to the rubber powder. It was found that the tensile-compression ratio of the thermal insulation slurry and the cellulose content were higher, and the higher the tensile-pressure ratio was. However, excessive amounts of cellulose incorporated into the thermal insulation slurry are detrimental to the softening coefficient, resulting in a sharp drop in the softening coefficient, as shown by 圄4. This is because cellulose is a water-soluble polymer compound. On the one hand, it can increase the viscosity of the slurry and further improve the workability and increase the tensile strength. On the other hand, cellulose has a certain solubility in water. When it comes into contact with water, it dissolves into the water from the polymer film. When the amount of cellulose is large, the dissolution of the vitamins will destroy the uniformity of the polymer film. As a result, the strength of the thermal insulation slurry is greatly reduced, and the softening coefficient is also reduced.

1.3 Optimized screening of mix ratio Based on the previous test conclusions, the composition and ratio of the thermal insulation slurry were determined by analysis and comparison and retesting. Overall, the optimum ratio of rubber powder to polystyrene particles (density at 1447 kg/m3) is: kg rubber powder 9L polyphenyl particles (bulk volume). Since the density of polyphenylene particles varies greatly, the amount of polyphenylene granules in this ratio is preferably measured by volume. The optimum ratio (mass fraction) of each component is cement, 76.5%; fly ash, 10% calcium oxide, hybrid fiber, 1.5% rubber powder, cellulose, 4% air entraining agent, 03% water agent, 0.6% Other admixtures 0.1%. The main properties of the thermal insulation slurry prepared by the optimized mixing ratio are shown in Table 1.

Table 1 Main properties of thermal insulation slurry Compressive strength Tensile strength Softening coefficient Dry apparent density Thermal conductivity 2 Measurement of thermal expansion coefficient of thermal insulation slurry and behavior under wet conditions This study uses concrete temperature linear expansion coefficient tester, The thermal expansion coefficient of the thermal insulation slurry was measured and its behavior under warm conditions was studied.

The concrete temperature linear expansion coefficient measuring instrument is composed of hardware and control software. The hardware part mainly includes the measuring and controlling part and the heating water tank.

2.1 Determination of thermal expansion coefficient of thermal insulation slurry Considering the structural characteristics of the concrete temperature linear expansion coefficient tester and the difficulty of water bath heating on the sealing of the dry test block. The test uses the dry test block to measure the thermal expansion coefficient of the thermal insulation slurry from the high temperature in the sealing condition to lower the temperature.圄5 is a test curve and a fitting curve of the thermal insulation slurry shrinking from a (72±1) C to a steady state in a dry state under a dry state.

The measurement curve and fitting curve of the thermal expansion coefficient of the thermal insulation slurry can be seen from 圄5. The time from the cooling of the test block to the steady state in the constant temperature environment is 24h. At the same time, according to the test data, calculate the linear thermal expansion coefficient of the thermal insulation slurry in the dry state. a: 72-17 2.2 The swelling curve of the thermal insulation slurry. The test also absorbs the thermal insulation slurry from the dry state to different water content at room temperature. The deformation at the time of stable rate was measured as shown in Fig. 6.

The relationship between the deformation rate and the water content of the thermal insulation slurry at room temperature can be seen from 圄6, and the moisture has a great influence on the deformation of the thermal insulation slurry at low water content, although it is linear. As the water content increases, the sensitivity of the thermal insulation slurry to moisture decreases.

Comparing 圄5 and 圄6, it can be seen that under the condition of low water content (less than 4%), the effect of moisture on the deformation of the thermal insulation slurry is obviously greater than the influence of temperature on its deformation.

The deformation ratio of the thermal insulation slurry in the temperature change range of 55 C is 4.8×10 −4 , and the deformation caused by the change of the water content by one percentage point is equivalent thereto.

At the same time, the test also measured the deformation of the dry insulation slurry test piece under the condition of constant temperature.圄7 is an expansion curve of the thermal insulation slurry from the dry state to the final moisture content of 1.64% in an environment of temperature (17 ±) C relative temperature (38 ±)%.

Time. The swelling curve of the thermal insulation slurry under constant temperature and humidity conditions can be seen from 圄7, and the temperature balance of the thermal insulation slurry is a very slow process. Therefore, it can be concluded that the change of the ambient temperature in a short period of time (such as day and night) has little effect on the deformation of the thermal insulation slurry, and the change of the ambient temperature over a long period of time (such as seasonal changes) may have a greater impact on its deformation.

3 Conclusions In this study, the optimized ratio of thermal insulation slurry was obtained through a large number of experiments and the behavior of the thermal insulation slurry under warm conditions was preliminarily studied.

(1) The optimized ratio (mass fraction) of the thermal insulation slurry is cement, 76.5%; fly ash, 10%; calcium oxide, mixed fiber, 1.5%, rubber powder; 6%; cellulose. 4% air entraining agent. 03% water,. 6% other admixtures 0.1%. Experimental study on the connection of cogging polystyrene board and concrete pouring. Yu Xiaojing, Wang Mingping, Liu Junchang, Liu Wei (School of Civil Engineering, Qingdao Technological University, Qingdao 26633, Shandong, China) And verified the important role of interface mortar in the external insulation system.

Expanded polystyrene foam sheet (hereinafter referred to as polystyrene board) is often used for exterior insulation. The cast-in-place concrete composite meshless polystyrene board external thermal insulation system is one of the five external wall thermal insulation systems recommended in the G144-2004 external wall thermal insulation engineering technical specification. In this paper, the coupling strength of the cogged polystyrene board and concrete in the system is tested with the inclination angle of the cogging, the cogging and the flexural strength of the polystyrene board. The effect of the interface mortar is verified.

Fund Project: Shandong Provincial Education Department Science and Technology Plan Project (05F02) 1 The construction of the cogging polystyrene board of the cogging polystyrene board is as shown, the middle tooth groove is a horizontal rectangular groove, = b=100 Xinjiang, = 10 Xinjiang, 0 = 90 °. The middle cogging is a-toothed groove for the configuration of the pitched polystyrene board; - the top of the tooth is the thickness of the H-polystyrene board a tooth inclination; - the height of the tooth (2) the insulating slurry is within 1742t The linear thermal expansion system) under the condition of low water content (less than 4%), the effect of moisture on the deformation of the thermal insulation slurry is significantly greater than the influence of temperature on the deformation of the thermal insulation slurry. The change of ambient humidity alternating around day and night has little effect on the deformation of the thermal insulation slurry, and the seasonal environmental humidity change may have a greater impact on the deformation of the thermal insulation slurry.

(Finish)

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