Effect of Emulsified Asphalt on Performance of Thermal Insulating Mortar of Glass Beads
Foreword With the development of our country's economy, energy consumption has increased dramatically. Energy shortages have jeopardized the implementation of social sustainable development strategies. Building energy consumption is a major energy consumption in China. Therefore, building energy conservation has become an important part of energy-saving systems. One of the main ways of building energy efficiency is to use insulation materials to reduce the energy consumption of buildings. In addition, in some large-scale water conservancy projects (such as channels, aqueducts, etc.), in order to prevent the cracking of thin-wall concrete, insulation materials are also needed. At present, the commonly used insulation materials are mainly organic materials. Although such materials have good thermal insulation properties, they have poor weatherability and are prone to aging. Compared with organic insulation materials, inorganic thermal insulation mortar has the characteristics of strength, durability and fire resistance.
Vitrified beads insulation mortar as a new type of inorganic insulation materials on the market, overcomes the shortcomings of traditional inorganic insulation mortar such as poor workability, poor insulation, and other shortcomings, but the glass beads insulation mortar is a brittle material, prone to dry shrinkage cracking, Affected its service life. In addition, the vitrification beads in the glass beads heat preservation mortar have higher water absorption rate, and the thermal conductivity increases rapidly after water absorption, and the heat preservation effect drops sharply. Therefore, it is necessary to modify the glass beads insulation mortar. Meng Qinglin et al.151 modified the vitrified microbeads with organic laurel aqueous solution. The results show that silicone water repellent can significantly reduce the water absorption rate of vitrified microspheres, but the vitrified microbead insulation mortar still has poor flexibility and ease. Cracking and other shortcomings.
In this paper, the effect of emulsified asphalt on the apparent density, compressive strength, flexural strength, water absorption and thermal conductivity of the heat-insulating mortar of vitrified microbeads was studied by adding emulsified asphalt to the heat-insulating mortar.
Scientific and technological research projects: "5" National Science and Technology Support Plan (2006BAB04A02).
1 Experimental part 1.1 Raw materials Cement: 32.5R ordinary portland cement, produced by Huaxin Cement Co., Ltd.; vitrified microbeads: provided by Wuhan Lakeline Technology Co., Ltd.; emulsified asphalt: solids content 55%, its properties are shown in Table 1; The main ingredients are hydroxypropyl methyl cellulose ether, powder, national starch production; defoamer, tributyl phosphate.
Table 1 Performance Composition of Emulsified Asphalt/% Appearance Polar Evaporation Residual Remaining Residue/% Type Cationic Water Balance/% Tea Brown Bisexual Partial Yang Cationic Slow Cracking 1.2 Mixture Ratio of Thermal Insulation Mortar Design and Preparation Basic Ingredients of Thermal Insulating Mortar See Table 2, on the basis of the above mix ratio, the amount of emulsified asphalt is changed, and the ratio of asphalt ash (the ratio of asphalt to cement used in emulsified asphalt) is 5%, 10%, 15%, and 20%, respectively. The beads and the water-retaining agent were evenly mixed, and the mixture was stirred with water for 2 minutes. Then the emulsified tobacco smoke with the defoamer added thereto was stirred for 2 minutes to control the fluidity at 140±5 mm. The heat-preserving sand dish was mixed and molded to prepare test pieces. Under normal conditions, 28 days, test its performance.
Table 2 Ratio of thermal insulation mortar Cement vitrification microspheres Water-retaining agent Defoamer Dosage / Wt% amount 1.3 Performance test Dry mortar of dry apparent density, compressive strength and flexural strength Reference JGr/0-90 "Construction Basic Performance Test Method for Mortar", thermal conductivity determined according to GBAT10294-1988.
Mi soaked in water sample quality, g; m dried sample quality, g 2 results and discussion 2.1 The impact of emulsified asphalt content on the apparent density of vitrified microbead insulation mortar The emulsified asphalt content of vitrified microbead insulation mortar The effect of dry apparent density. It can be seen that the apparent density of the heat-insulating mortar for vitrified microbeads shows a clear downward trend with the increase of emulsified asphalt content. When the ratio of leachate to lime is 10%, the dry apparent density is 11% lower than that when it is not added, and when the ratio of leach gray to 20% is reached, the dry apparent density is reduced by 15%. This may be due to the surface contained in the emulsified asphalt. The active agent, caused by the introduction of a certain amount of air bubbles during the mixing and stirring of the vitrified microbead insulation mortar.
2.2 The effect of emulsified asphalt on the mechanical properties of vitrified microbead insulation mortar The results of emulsified asphalt on the compressive strength and flexural strength of vitrified microbead insulation mortar are shown in the following. It can be seen that the compressive strength and flexural strength of the emulsified asphalt-modified vitreous bead thermal insulation mortar first increase and then decrease with the increase of the ratio of leachate ash.
When the ratio of leachate to ash is 5%, the compressive strength and flexural strength are increased by 2.8% and 14.1%, respectively, when they are not added. However, when the ratio of leach gray is greater than 5%, the compressive strength of the bead insulation mortar is Both the flexural strength and the flexural strength showed a gradual decline. This is due to emulsified asphalt added to the mixture, the emulsified asphalt and cement hydration products synergistically form a network structure, from the gelling effect, so when the amount of emulsified asphalt is less, it is higher than when not added; but with As the amount of emulsified asphalt gradually increases, emulsified asphalt will hinder the hydration of cement, and more and more cement particles surrounded by emulsified asphalt will not be fully hydrated, limiting the formation and connection of cement hydration products. The cementing effect of cement cannot be fully exerted. Therefore, when the ratio of leach gray is greater than 5%, the strength tends to decrease.
The effect of emulsified asphalt on the compressive strength and flexural strength of vitrified microbead insulation mortar The material's crush ratio, which is the ratio of the compressive strength and flexural strength of the material, can indirectly reflect the ductile and brittleness of the material. The effect of the amount of emulsified asphalt on the compression ratio of heat-insulating mortar for vitrified microbeads. It can be seen that with the increase of the amount of emulsified asphalt, the pressure-folding ratio is gradually decreasing. The larger the compression ratio, the greater the brittleness of the material and the poorer the toughness; conversely, the smaller the compression ratio, the smaller the brittleness of the material and the better the properties. This shows that with the increase of the ratio of leach gray, emulsified asphalt modified glass beads thermal insulation mortar brittle, toughness increases.
2.3 The effect of emulsified asphalt content on the water absorption of the glass bead insulation mortar is the effect of emulsified asphalt content on the water absorption of the insulation mortar. It can be seen that the water absorption of the heat-insulating bead of the vitrified microsphere decreases significantly with the increase of the ratio of the leachate ash. When the ratio of the leach-ash is 10%, the water absorption ratio is decreased by 58.8% compared with the case where the leach-ash ratio is not added. However, when the ratio of the leachate is At 20%, the water absorption rate was only 66.2% lower than when it was not added. This shows that the water absorption rate does not change significantly with the ratio of the drain ash when the ratio of the ash ratio exceeds 10%. This is due to the fact that the emulsified bitumen blocks large pore passages between the cement hydration products, and on the other hand, after mixing with the thermal insulation mortar, the emulsified asphalt is covered on the surface of the thermal insulation aggregate to prevent water from intruding into the thermal insulation aggregate, thereby reducing the thermal insulation. Mortar water absorption. However, with the increase of the amount of emulsified asphalt, the emulsified asphalt covering the insulating aggregate tends to be saturated. Therefore, when the amount of emulsified asphalt is increased, the water absorption rate of the thermal insulation mortar tends to be gentle.
%: Effect of Guanlan Huili emulsified asphalt on the water absorption rate of vitrified microbead insulation mortar 2.4 Emulsified asphalt vs. vitrified microbeads Heat-retaining and sand-removing machinery Both stools are scratched 2*-5/*â–¡ grazing reflects the emulsified asphalt The effect of thermal conductivity of glass beads on thermal insulation mortar. It can be seen that with the increase of the ratio of leachate ash, the thermal conductivity of the thermal insulation material has decreased, indicating that the addition of emulsified asphalt improves the thermal insulation effect of the thermal insulation mortar of glass beads. This is due to the incorporation of emulsified bitumen. Although the amount of macropores in the heat-insulating bead of vitrified microbeads is reduced, emulsified pitch contains surfactants, and a certain amount is also introduced during the mixing and stirring of the heat-insulating mortar of vitrified microbeads. The bubbles increase the number of small holes in the thermal insulation mortar, which is beneficial to the improvement of thermal insulation effect of the thermal insulation mortar.
The effect of emulsified asphalt on the thermal conductivity of vitrified microbead insulation mortar is as follows: (1) Emulsified asphalt can significantly reduce the dry apparent density of vitrified microbead insulation mortar.
Emulsified asphalt can improve the flexural strength of the glass beads insulation mortar, and also have a certain improvement in the compressive strength. However, with the increase of the amount of emulsified asphalt, compressive strength and flexural strength all showed a downward trend. However, the ratio of pressure to compression decreased with the increase of the amount of emulsified asphalt, indicating that the emulsified asphalt reduced the brittleness of the heat-insulating bead of the vitrified microbeads and enhanced the toughness of the heat-insulating mortar of the vitrified microbeads.
The incorporation of emulsified asphalt can significantly reduce the water absorption of the heat-insulating bead of the vitrified microbeads, and the heat-insulating properties of the vitrified microbead insulation mortar are improved.
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