Development of lightweight self-insulating block with high content of fly ash

With the reform of wall materials and the in-depth development of building energy conservation, the goal of building energy efficiency of 65%1 puts higher requirements on the performance of new wall materials. Especially in the construction of new countryside in China, a lot of new building materials with light weight, high strength, thermal insulation, environmental protection and energy saving, low price and good quality, and local materials can be needed. In this environment, based on the full study of the performance of the wall material, we determined that the fly ash non-calcined light aggregate (commonly known as fly ash free-burning ceramsite, the same below) produces thin-walled concrete hollow block as the shell. The development of fly ash lightweight self-insulating block with ultra-light fly ash foam concrete as insulation core material, research, design, production and popularization of its structure formation, material composition and production process.

1 Lightweight self-insulating block material Lightweight self-insulating block shell material adopts fly ash non-calcined light aggregate, construction waste is light aggregate, slag powder, fly ash, calcium carbide slag, admixture Cement. The dry bulk density of concrete is designed to be 1100~1200kg/m3, which is formed by vibration of automatic block making machine. The core material is mechanically used to make fly ash, slag powder, cement, calcium carbide slag, polymer composite admixture, water, etc. The slurry is made into a slurry, and the inorganic foaming agent is added to the ultra-light fly ash slag foam. The president of Shiyong Waste Slag Energy Saving Building Materials Co., Ltd. is engaged in the research, production and promotion of environmental protection and energy-saving building materials. Application work. The project has won the second prize of Chifeng Science and Technology Progress Award and has been approved for promotion and application in Inner Mongolia Autonomous Region.

In the cavity of the block, foaming, forming, and atmospheric pressure steam curing, making fly ash lightweight self-insulating block, the structure of the block can be used as a single row of holes on both sides with grooved double row holes and three rows Holes, the application is better by changing the shape of the block 2, so that there is a sandwich insulation material at any position on the cross section of the wall after the masonry, so that the thermal bridge formed by the block wall and the rib can be effectively solved. The products are lighter, environmentally friendly and energy-saving, the wall structure is stronger and safer, and the building is more convenient. The dry bulk density of the lightweight self-insulating block is designed to be 600~900kg/m3, and the compressive strength is designed to be 3.5~7.5MPa. The main specifications of the lightweight self-insulating block are: 190mm inner wall partition wall block is 390mmX 190mm It is convenient to fix the strength of the block and the wall-mounted heating facilities. The wall thickness of the block is 22mm~25mm. 1.1 The raw materials of the material include: (1) The original humidified fly ash of the coal-fired power plant ( The chemical composition is shown in Table 1). (2) The properties of fly ash non-calcined light aggregates are shown in Table 2. (3) Construction waste, which is used for aggregate after sorting and crushing, and the classification of construction waste particles after crushing and screening is shown in Table 3. (4) Carbide slag: Select acetylene residue from chemical plant. The main chemical composition is shown in Table 4. (5) Slag powder: The slag powder produced by Dongxu Slag Grinding Co., Ltd. is selected. The main chemical composition is shown in Table 5. (6) Foaming Agent: The inorganic chemical foaming agent is selected. The foaming agent is a key component of the foamed concrete matrix. It can reduce the density of the product and improve the energy-saving performance and durability of the product. (7) Desulfurization gypsum: The waste residue after desulfurization of Chifeng Power Plant is adopted.

(8) Polymer composite admixture: self-made raw materials.

Table 1 Chemical composition of fly ash Table 2 Product properties of fly ash non-calcined light aggregate (commonly known as fly ash free-burning ceramsite) Shell molding, foam concrete core material slurry preparation and casting, steam curing, etc. Process composition. The production process is divided into -3. Fly ash - 黾 黾 slag powder - 黾 黾 黾 黾 一 一 计量 计量 计量 计量 计量 计量 计量 计量 计量 计量 计量 计量 计量 ― ― ― ― ― ― ― ― ― ― ― ― ― ― ― ― - - - - - - - ~Measure "Qualification particle size loose dry density tube pressure strength stability 1h water absorption rate carbonization softening /% coefficient coefficient SO3 loss of ignition fly ash non-calcined light aggregate production process fly ash one> count one machine slag powder一―- 计 童 械 粉 粉 电 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 洧 ( ( ( ( ( ( ( Mixing ratio (lightweight aggregate per cubic): 672kg fly ash; 64kg slag powder; 48kg calcium carbide slag; 16kg desulfurization gypsum; 2kg admixture. (2) Shell ratio (per cubic block): slag powder 100kg Fly ash 139kg; calcium carbide slag 66kg; fly ash non-calcined light aggregate 200kg; desulfurization gypsum 5kg; construction waste 80kg; admixture 3kg; (3) core material ratio (per cubic foam concrete dosage): slag powder 40kg ; 30kg of fly ash; 60kg of ordinary Portland cement, 25kg of calcium carbide slag; 5kg of desulfurized gypsum; 5,4kg; admixture 2,4kg, water fly ash light self-insulating block production is divided into raw material detection, measurement, fly ash non-calcined light aggregate, fly ash slag mixture preparation, concrete + metering powder Coal ash non-calcined light aggregate one metering one construction waste - meter f polymer composite type admixture one metering fly ash slag mixture - metering one polymer compound type admixture one metering one foaming agent - iff-foaming machine F--mixer belt conveyor automatic forming machine hollow shell-self-protection block blank body atmospheric pressure steam curing inspection automatic:; pulp machine fly ash self-insulation block production process 3 performance and analysis product quality test preparation The fly ash lightweight self-insulating block is tested by the National Building Materials Industrial Building Materials Quality Supervision and Inspection Center according to GB/T15229-2002 light aggregate concrete small hollow block. The results are shown in Table 6. As can be seen from Table 6, The performance of the fly ash lightweight self-insulating block meets the requirements of GB/T15229-2002. The main technical indicators have a density grade of 700, a strength grade of 5.0, a water absorption rate of 13.6%, a carbonization coefficient of 0.96, and a softening coefficient of 0. 92, frost resistance and The radioactivity meets the requirements.

Table 6: Fly ash lightweight self-insulating block performance test results test indicators standard requirements measured dry bulk density / kg / m3 compressive strength / MPa dry shrinkage /% carbonization coefficient water absorption /% capacity 20 softening coefficient frost resistance 45~20t25 times qualified loss/%/radioactive external exposure index/ly internal exposure index/lRa 3.2 Thermal performance test and analysis Test the thermal conductivity of fly ash lightweight self-insulating block housing and core material. And compared with the heat transfer coefficient of the thermal insulation block masonry simulation test.

3.2.1 Material thermal conductivity test The thermal conductivity is tested by the heat-proof plate method. According to the sample specifications required by the DRP4A thermal conductivity tester, the thermal conductivity test samples are prepared according to the production ingredients. The test results are shown in Table 7. Table 7 The thermal properties of the fly ash lightweight self-insulating block thermal performance project performance index shell thermal conductivity / [W /(m core material thermal conductivity / [W / (m heat insulation coefficient of insulation block (calculation) / [heat transfer coefficient of insulation block masonry / (test) 3.2.2 thermal resistance or average heat transfer of the block Calculate the coefficient, the calculation result of heat transfer coefficient is shown in Table 7. It can be seen from Table 7 that the heat transfer coefficient test value of the lightweight self-insulating block masonry is higher than the calculated value, which is due to the cold bridge H of the masonry joint. The effect is caused, but it can still meet the energy-saving requirements of the wall structure of the outer protective structure in cold regions of China.

3.2.3 Economic analysis Through the quota calculation, the self-insulation system of the fly ash lightweight self-insulating block is compared with the cost of the autoclaved aerated concrete block of Chifeng City and the external thermal insulation system of the sintered hollow block. The results are shown in Table 8. Table 8 different wall materials exterior wall building energy-saving practices cost comparison system wall material masonry material cost / yuan / m3 self-heating 240mm thick fly ash self-insulation block waste slag insulation masonry mortar + waste slag anti-cracking plaster mortar Insulation 240mm thick clay sintered hollow block special interface agent + bonded mortar + insulation board + crack resistant mortar + mesh cloth + flexible putty 300mm thick autoclaved steam concrete block special interface agent + insulation slurry + cracking mortar + Paving steel mesh + crack resistant mortar + flexible putty Although the unit price per cubic meter of fly ash lightweight self-insulating block is higher than the other two materials, it can be seen from Table 8 that the other two materials need to be externally insulated. The external thermal insulation system requires more supporting materials, complicated practices and poor safety factor. Therefore, from the comprehensive cost analysis of the unit area wall, the price advantage of the fly ash lightweight self-insulating block is obvious.

At the same time, the quality of fly ash lightweight self-insulating block masonry is easy to control, which can fundamentally guarantee the quality of the project.

4 Conclusion The fly ash lightweight self-insulating block has the characteristics of light weight, A1 fireproof, high strength, thermal insulation and energy saving, durability and life expectancy with buildings. Masonry and insulation are completed once, and the insulation problem of buildings is solved from the structure. At the same time, it also speeds up the construction speed, improves the quality of the masonry, and is beneficial to the seismic performance of the masonry, which reduces the construction cost.

The average heat transfer coefficient of the wall made of fly ash lightweight self-insulating block is 0.521WKm2K), which can meet the energy-saving requirements of the wall structure of the outer protective structure in cold regions and cold and hot summer regions of China, and is suitable for the framework of urban and rural construction. Structured infill walls and load-bearing walls, as well as insulated roofing or floor heating works.

The raw materials required for the production of fly ash lightweight self-insulating blocks are solid waste and are readily available. At the same time, it is conducive to purifying the environment and protecting the country. Advanced production technology, reliable product quality, suitable for large-scale automatic and semi-automatic large, medium and small production lines for large-scale production. It is an environmentally-friendly and energy-saving multifunctional new wall material with excellent performance and obvious price advantage. It is worthy of widespread application.

(Finish)

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