Experimental Study on Performance of EPS Thermal Insulation in Journal of Harbin Engineering University Chen Bing, Liu Ning, Deng Chuqing (School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiaotong University, Shanghai 200240, China) The amount of agent and fly ash added to EPS insulation mortar, workability, mechanical properties and thermal conductivity And the effect of water absorption and softening coefficient. The test results show that for the preparation of high performance EPS thermal insulation mortar, the volume of EPS volume is suitably controlled to be 80%~82%, the gas content is about 20%, and the fly ash content is 20%. Adding appropriate amount of commercially available white latex can improve The bond strength and flexural strength of EPS thermal insulation mortar, the amount of fly ash can significantly reduce the shrinkage and thermal conductivity of EPS thermal insulation mortar, and improve the overall performance of EPS thermal insulation mortar.
Online publishing address: http: EPS thermal insulation mortar prepared by using polystyrene foam (EPS) particles as light aggregate. Because it can be used for exterior insulation system, it breaks through the limitation that traditional thermal insulation mortar can only be used for internal insulation. The attention of the engineering community. Since 2000, the research and development of EPS thermal insulation mortar has been started in China, and it has been applied in engineering. M. At present, more researches are on EPS thermal insulation mortar ratio, process, performance and engineering application. Wang Wei H studied the effects of air entraining agent, latex powder and cellulose ether on the performance of EPS thermal insulation mortar, and considered the fund project: National Natural Science Foundation of China (50708059); Key Laboratory of Advanced Civil Engineering Materials Ministry of Education (Tongji University) ) funded projects open communication oF: Bing, E-mail EPS thermal insulation performance with the dosage of air-entraining agent and latex primer powder is improved to increase, after the increase with the dosage of the cellulose ether becomes better to deteriorate, and It is believed that the dry apparent density and thermal conductivity of the thermal insulation mortar can be predicted by measuring the gas content of the EPS thermal insulation mortar. Zhang Guihong 5 studied the improvement of the crack resistance of the mortar by adding polypropylene fiber to the mortar mixture. When the amount of propylene fiber is 0.1%, the crack resistance is the best. In view of the phenomenon that the EPS particles do not affinity with the cement slurry, the researchers used the method of adding the binder component to the mortar mixture to improve the bonding property M of the EPS particles and the cement paste, and proposed two on the basis of this. Submixed preparation process 08. Although there has been a lot of research work around EPS insulation mortar, there is no systematic study on how to improve and improve the overall performance of EPS insulation mortar. In this paper, the comprehensive performance of warm mortar, including workability, mechanical properties, water absorption, softening coefficient and thermal conductivity, and the technical means to prepare EPS thermal insulation mortar with better comprehensive performance.
1 Test 1.1 Raw materials 1) Cement: 42.5 grade ordinary Portland cement, its 28d compressive strength is 57.5MPa, the mineral composition is shown in Table 1. Fly ash: n grade fly ash produced by Shanghai Wujing Power Plant, see the specific ingredients Table 1. EPS particles: primary polystyrene foam particles, particle size 1.0~2.5mm, bulk density binder: using commercially available water-soluble polyvinyl formal adhesive (ie building 801 glue, referred to as Z) and Polyvinyl acetate emulsion (ie white latex, referred to as BR).
Air entraining agent: produced by Shanghai Grace Building Materials Co., Ltd. Table 1 Cementing material Chemical composition Loss of ignition Cement fly ash 1.2 Sample preparation Mix cement, fly ash and various additives evenly, add water to stir for 2 min and then add EPS particles. After stirring for 3 minutes, the fresh mortar mixture was partially used for the test of workability and gas content, and the other part was used for the test of dry apparent density, thermal conductivity and other properties. After the test piece is formed, it is placed in an environment with a temperature of (20 ± 2) C and a relative humidity of (60 ± 10)%. After 72 hours, the mold is removed, and the test is continued until the specified age.
1.3 Performance test and suitability test: Refer to the People's Republic of China industry standard G70-K) <Basic performance test method for building mortar to test consistency and stratification.
Strength test: The compressive and flexural strengths are carried out according to GB/T17671-1999 cement mortar strength test method (ISO method), and the sample size is 40mmX40mmX160mm.
Water absorption and softening coefficient test: Refer to G514002 concrete technical regulations. The test pieces used in the experiment were made into three groups, which were taken from the same proportion of mortar. The three test pieces were: thin 2 results analysis and discussion 2.1 The effect of the amount of EPS was studied, the water-cement ratio was controlled to 0.45. A sample was prepared using a water-soluble polyvinyl formal adhesive (Z) mixed with different volumes of EPS particles. The test results are shown in Table 2. Table 2 The effect of EPS volume on the performance of EPS thermal insulation mortar Table content / % consistency Apparent density Water absorption coefficient Thermal conductivity / Mechanical properties Compressive strength / MPa Flexural strength / MPa Softening coefficient Note: F / C refers to the folding ratio. It can be seen from the table that the consistency of the mortar mixture gradually deteriorates with the addition of the EPS particles after the EPS slurry is used to bond and lubricate the bone. . This is mainly because the slurry portion of the water material is reduced, resulting in a decrease in flow properties. Since the EPS particle quality is significantly lighter than the cement slurry, the dry density of the EPS thermal insulation mortar decreases as the EPS volume is increased. For the water absorption rate of EPS thermal insulation mortar, with the change of EPS volume, there is an optimum value, which is mainly because the EPS particles themselves are hydrophobic, and the water absorption rate decreases as the EP volume is increased, but when When the amount of EPS is high, the pores inside it increase, and the structure is not dense, resulting in an increase in water absorption. For mechanical properties, as the volume of EPS volume increases, the cement slurry required for the aggregate is increased, while the cement slurry used to bond the aggregate is relatively reduced, and the bond between the lightweight aggregates When it becomes smaller, the compressive strength and flexural strength of mortar are obviously decreased. In comparison, the relationship between softening coefficient and EPS volume is more complicated. The initial softening coefficient decreases with the increase of EPS particle volume percentage. After accounting for more than 82% of the mortar mixture, the softening coefficient of the mortar test block decreases, and the softening coefficient is maintained in the relationship between the dry density of the EPS thermal insulation mortar and the thermal conductivity and compressive strength. Fig. gives the dry density of the EPS thermal insulation mortar. Relationship with thermal conductivity and compressive strength. It can be seen that the compressive strength and thermal conductivity of EPS mortar increase with the increase of dry density. For EPS thermal insulation mortar, in order to achieve its thermal insulation performance, it is desirable that the thermal conductivity is as small as possible, and in order to ensure its good engineering application, it needs to have sufficient strength, which are contradictory. It shows that when the dry density of EPS mortar is 250 ~ 320kg / m3, its thermal conductivity and compressive strength change with the dry density, and can meet the requirements of engineering application.
2.2 The influence of binder EPS granule is a kind of non-polar lightweight material. When it is used as the main lightweight aggregate to prepare EPS thermal insulation mortar, if it is directly mixed with cement mortar, the cement mortar will not wet it. The bonding strength between the two interfaces is weak, which results in poor construction and ease of mortar, and is difficult to construct. In order to improve the wetting affinity between cement mortar and EPS foam particles, it is an effective method to add binder to mortar mixture. 910. Most of the current research is to use EPS to carry out EPS particles. Surface modification and good results. However, because the dispersible polymer powder is expensive, it is not conducive to the promotion and use of the finished product.
In this study, two common and inexpensive binders were used for experiments: water-soluble polyvinyl formal adhesive (ie, building 801 glue, referred to as Z) and polyvinyl acetate emulsion (ie, white latex, referred to as BR). In the experiment, the EPS volume is fixed at 81.8%, and the Z-gel ratio is controlled to 0.45, and the substituted cement is 10%, 2%, 4%, and 16%, respectively; In order to achieve a suitable range of consistency values, the water-cement ratio was adjusted to 0.55 after the test, and the substituted cement content was 4%, 0%, respectively. Table 3 shows that Z and BR rubbers are replaced by different cements. The effect of EPS insulation mortar performance. It can be seen from the table that for Z-gel, the amount of the mixture has a great influence on the consistency value, and the consistency value increases with the increase of the rubber content. The mortar mixture prepared at the dosage of 10% can not meet the construction requirements; At the same time, it is also found that the dry density of the mortar specimen increases with the increase of the binder amount, but the increase is not large. When the dosage is 16%, the dry density only increases by 3.8%; the water absorption of the specimen increases with the Z-gel. The amount of water increased slightly, and when the amount reached 14%, the water absorption rate increased rapidly. For BR glue, the influence law is the same as that of Z glue.
Table 3 The effect of different amounts of Z and BR glue on the performance of EPS thermal insulation mortar Table glue admixture consistency apparent density water absorption strength / MPa softening coefficient compressive strength flexural strength bond strength (a) Z content impact The effect of different amounts of Z and BR rubber on the compressive strength and flexural strength of EPS thermal insulation mortar can be seen from the test data of Table 3: for Z rubber. With the increase of rubber content, the compressive strength of the test piece decreased slightly. When the dosage was 10%~12%, the compressive strength decreased greatly; the flexural strength increased slightly, when the dosage was 14% larger. At the same time, the flexural strength decreases; the folding ratio reaches the maximum at the blending amount of 14%, which is 0.45; the bond strength also reaches the maximum when the blending amount is 12% to 14%; the softening coefficient follows the Z-gel The increase is reduced, and tends to be gentle when the amount is more than 14%, and both are lower than 0.5. For BR glue. With the increase of rubber content, the compressive strength value of the test piece first increased slightly. When the dosage was more than 8%, the compressive strength decreased. When the blending strength was between 6% and 10%, the increase was observed. Larger (increased by 21.6%); the bond strength also increased with the increase of BR rubber content, and the bond strength value increased by 27.8% when the content was 10%; the softening coefficient of the test piece of this group The values ​​are all greater than 0.6 and increase with the increase of the amount of BR glue.
It can be seen from the test results that with the increase of binder content, the compressive strength of EPS mortar specimens changes little or even slightly; the flexural strength and the compression ratio are improved, indicating EPS insulation mortar The toughness and adhesion have been improved. There are three reasons for the improvement of the flexural strength and the folding ratio of EPS thermal insulation mortar after adding binder: 1) In the process of coagulation hardening of mortar, the binder will be in the transition zone between EPS particles and cement paste. Drying into a film, the interface between the two is more dense and firm; 2) some of the binder is dispersed into the cement slurry, and as the cement hydrates, the binder aggregates into a film to form a polymer network. The elastic modulus of the material network is lower than the elastic modulus of the cement hardened body, which improves the toughness of the hardened cement paste; 3) some polar groups in the polymer molecule may also chemically interact with the cement hydration product to form Special bridge function to improve the physical structure of cement hydration products, relieve internal stress, and thus reduce the generation of micro-cracks in cement paste.
(b) The effect of BR content on the compressive strength and flexural strength of EPS thermal insulation mortar with different amounts of Z and BR rubber. Fig. 2Effectofdifferentaddition 2.3 In the study of the influence of air entraining agent, the water-cement ratio of the sample is controlled to 0.55. The volume of EPS is 81.8%, the content of BR is 6%, and the amount of air entraining agent is 0%05%10%15% of EPS volume. The effect of different amount of air entraining agent on the performance of EPS thermal insulation mortar See Table 4. Table 4 Effect of Air Entraining Agent Content on Performance of EPS Thermal Insulation Table No. Air Volume and Ease Dry Density Water Absorption Rate Thermal Conductivity Compressive Strength Softening Coefficient Consistency/cm Stratification See Table 4 The consistency of the mortar is obviously improved after the addition of the air entraining agent; while the stratification degree increases slightly with the increase of the amount of the air entraining agent; the dry density of the sample decreases with the increase of the gas content, and the sample No. Y3 is dried. The density decreased by 13% compared with Y. The compressive strength of the sample gradually decreased with the increase of gas content. Before the gas content reached 20.1%, the compressive strength decreased not significantly, and the use of air entraining agent was also observed. The effect on the softening coefficient is not significant, and the introduction of air entraining agent is beneficial to change The incorporation of air entraining agent has the most significant effect on the thermal conductivity of EPS thermal insulation mortar. With the increase of gas content, the thermal conductivity of the sample shows a significant downward trend. The thermal conductivity of sample No. Y3 is lower than that of Y. With 36.3%, the water absorption rate also decreased significantly with the increase of gas content.
The compressive strength and thermal conductivity of the comparative specimens vary with the increase of the gas content, and the appropriate introduction of bubbles is beneficial to formulating high-performance EPS thermal insulation mortar.
2.4 The influence of the amount of fly ash in the study The water-cement ratio of the sample is controlled to be 0.55, the volume of EPS is 81.8%, the amount of BR is 6%, and the fly ash is replaced by cement 0%, 0%. 0%, 0%, respectively, test their performance indicators such as compressive strength, dry shrinkage and thermal conductivity at different ages. The effects of different fly ash content on the compressive strength of EPS thermal insulation mortar are given. It can be seen from (a) that with the increase of curing age, the compressive strength of the sample is continuously improved, and the compressive strength of the test piece mixed with fly ash is obviously improved in the later stage, and both exceed the unfilled pulverized coal. Gray sample. (b) It shows that the compressive strength is the highest when the fly ash content is 20% at 28d age, and the compressive strength is the highest when the dosage is 90d. It can be seen that the addition of fly ash is advantageous for improving the late strength of the EPS thermal insulation mortar.
(b) Effect of fly ash content on 28d and 90d compressive strength on the compressive strength of EPS thermal insulation mortar. Fig.3Effectofdifferentfractions gives the dry shrinkage rate of EPS thermal insulation mortar with different fly ash content. Impact. It can be seen that after the 28-day-old period, the dry shrinkage rate of the test piece after the addition of fly ash is reduced. Among them, the dry shrinkage rate of the 40% test piece with the fly ash content is the smallest, and the dry shrinkage rate is 90d. Compared with the dry shrinkage rate at the 90-day age of the non-flying coal ash test block, 1.87%c was reduced by 67.9%. Compared with the dry shrinkage rate of the sample at 28d age, the relationship between the dry shrinkage rate and the fly ash content was observed. When the fly ash and the addition of 30%, the shrinkage ratio is larger, and the dry shrinkage rate of the fly ash-free sample is 1.99% c, and the minimum shrinkage rate is 0.99% when the blending is 40%. Compared with the ash sample, the dry shrinkage rate is reduced by 101%. Experiments show that adding appropriate amount of fly ash is beneficial to improve the shrinkage performance of EPS granule insulation mortar.
The effect of different fly ash content on the shrinkage rate of EPS thermal insulation mortar Fig.4Effectofdifferentfractions age/d the effect of different fly ash content on the thermal conductivity of EPS thermal insulation mortar Fig.5Effectofdifferentfractions gives the amount of fly ash to thermal conductivity Impact. As can be seen from the figure, as the test age is extended, the thermal conductivity is reduced. There is no obvious law on the influence of fly ash content on the thermal conductivity of EPS thermal insulation mortar: when the content of fly ash is 40%, the thermal conductivity is the largest, and then the minimum thermal conductivity is when the fly ash is 30%. The amount of fly ash is 20%. This may be caused by the increase of the amount of fly ash in the system, the cement cementing material is too small, and the through gap is formed in the system, causing air convection, resulting in an increase in thermal conductivity. In addition, the spherical glass beads contained in the fly ash also contribute to the improvement of the thermal conductivity of the mortar. However, when the amount of fly ash is large, it may have the opposite effect.
3 Conclusion With the increase of EPS volume, the consistency value of mortar mixture gradually deteriorated, and the compressive strength, flexural strength and softening coefficient showed a significant downward trend. When the volume of EPS is about 81%, the water absorption rate is the lowest. After that, as the volume percentage of EPS increases, the water absorption rate increases.
The thermal conductivity decreases with the increase of the EPS volume percentage. The EPS thermal insulation mortar is prepared. The suitable volume of EPS is 81%. The EPS insulation mortar consistency and water absorption increase with the increase of Z rubber content, and the strength values ​​are in Z rubber. When the amount is 14%, it reaches the maximum, and the softening coefficient decreases with the increase of Z rubber content. BR glue can greatly improve the flexural strength and bond strength of EPS thermal insulation mortar. The suitable content is 8%. Incorporation of air entraining agent It can significantly improve the consistency, water absorption, softening coefficient and thermal conductivity of EPS mortar, but the compressive strength is reduced. Considering comprehensively, the gas content in the EPS thermal insulation mortar is suitably controlled at about 20%.
Adding fly ash can significantly improve the late strength of EPS insulation mortar and reduce its shrinkage rate. The amount of fly ash has different effects on the thermal conductivity of EPS thermal insulation mortar, and the fly ash content is about 20%, and its thermal conductivity is the smallest. Considering comprehensively, the suitable dosage of fly ash is 20%.
(Finish)
The test bench was developed for Main Pump and motor of Bobcat Hydraulic pump truck, excavator, and rotary drill.
The test range, the test items and the test requirements are consistent with the JB/T7039-7044 and other relevant industry standards.
JUHENG can supply all kinds of Bobcat Excavator Parts like Bobcat Hydraulic Pump Spare Parts, etc,Bobcat Concrete Machinery Parts,Bobcat Excavator parts,
Bobcat Crane parts,Bobcat Pile Machinery parts,Bobcat Road construction machinery parts,Bobcat Port Machinery Parts, etc.such as pump walking motor rotary motor assembly and parts boom and arm cylinders seal repair kits all kinds of filter bucket bucket tooth and all Undercarriage Parts and so on.
Hydraulic Piston Pump, Duplex Pump, Short-Stroke Pump, Noise/Vibration Reduction, High Self-Priming Ability, Rotational Stability, High Efficiency, High Pressure, Compact Size, Reduction of Overall Length.
We export GENUINE PUMP, OEM PUMP, Bobcat Hydraulic Main Pump,Bobcat Main Hydraulic Pump,Bobcat Hydraulic Pump,Bobcat Hydraulic Pump Spare Parts, AFTERMARKET PUMP. We are specialized in OEM PUMP & AFTERMARKET PUMP. We export 95 NATIONS. Please contact us If you need STABLE SUPPLIER.
Bobcat Hydraulic Main Pump,Bobcat Main Hydraulic Pump,Bobcat Hydraulic Pump,Bobcat Hydraulic Pump Spare Parts,Bobcat Hydraulic Main Pump Assembly,Bobcat Main Pump,Bobcat Pump,Bobcat Hydraulic Parts,Bobcat Excavator Parts
Jining Juheng Hydraulic Machinery Co., Ltd. , https://www.jhexcavator.com