Thermal Insulation Mortar Research Articles

Innovative development of high-performance aerogel-phosphogypsum thermal insulation mortars: Optimization of composition and enhanced mechanical properties

This study investigates the effects of various components on the performance of aerogel-phosphogypsum (APG) thermal insulation mortar. This study investigates the effects of various components on the performance of aerogel-phosphogypsum (APG) thermal insulation mortar, with a special focus on optimizing the composition to enhance mechanical properties. The parametric range explored included phosphogypsum content from 10 to 30 wt%, hollow glass microspheres (HGS) from 5 to 15 wt%, and aerogel slurry from 40 to 80 wt%. Our findings reveal that the optimal composition, which provided the best balance between thermal insulation and mechanical strength, consisted of 20 wt% phosphogypsum, 10 wt% HGS, and 60 wt% aerogel slurry. Notably, the introduction of 0.14 % hydroxypropyl methylcellulose (HPMC) and 1.89 % re-dispersible polymer powder (RPP) significantly enhanced the compressive strength of the mortars. Specifically, compressive strength increased from an initial 0.05 MPa–0.27 MPa post-enhancement with HPMC and RPP. This research provides a detailed understanding of how individual components influence the formulation of APG and offers insights for optimizing the overall performance of aerogel-phosphogypsum composites, contributing to advancements in sustainable building materials.

Study on physical properties and snow-melting performance of multilayer composite conductive-pervious concrete for improving the snow-melting efficiency and energy consumption of ECON

One of the most significant challenges facing transport networks in cold regions is snow accumulation on road surfaces. This can lead to traffic congestion and safety issues. While electrically conductive concrete (ECON) heated pavement systems (HPS) offer several advantages, including stability, and low environmental impact, they also present certain limitations, such as low snow-melting efficiency and high snow-melting energy consumption. In this study, a SiO2 aerogel mortar thermal-insulation layer and a self-compacting concrete structural layer were set underneath the reduced graphene oxide (RGO) composite conductive concrete, and the straight pervious channels were prefabricated, to reduce the snow-melting efficiency and energy consumption through the preparation of multilayer composite conductive-pervious concrete integrated specimen. The initial objective was to investigate the influence of SiO2 aerogel substitution rate on the mechanical properties and thermal conductivity of thermal-insulation mortar. Secondly, the impact of the thickness of the conductive layer and thermal-insulation layer on the mechanical properties of the integrated specimen was analyzed. Finally, the impact of SiO2 aerogel thermal-insulation mortar and straight pervious channels on the integrated specimen's snow-melting performance was evaluated through a snow-melting test, which assessed the efficiency and energy consumption of the snow-melting process. The results indicate that when the SiO2 aerogel substitution rate was 40 %, the thermal-insulation mortar exhibited favorable mechanical and thermal-insulation properties. The 5 cm conductive layer and the 1 cm thermal-insulation layer achieved good mechanical properties of the integrated specimen. In comparison to single-layer composite conductive concrete, the snow-melting time and energy consumption of multilayer composite conductive-pervious concrete integrated specimen were reduced by 23.05 % and 21.30 %, respectively. The straight pervious channels permit the immediate discharge of water produced by snow melting, thereby reducing the heat transfer from the snow-melting board to the water film. The setting of SiO2 aerogel thermal-insulation mortar enables the retention of heat for the heating of the snow-melting board and snow melting, which improves the snow-melting performance.

Study on the properties and mechanisms of the glazed hollow bead thermal insulation mortar

With increasing concerns for energy conservation and environmental protection, research on glazed hollow bead thermal insulation mortar is of utmost importance. This type of mortar offers superior thermal insulation, leading to reduced energy consumption and emissions, in line with the current green building trends. This article aims to investigate the impact of varying component proportions on the parameters of thermal insulation mortar through an orthogonal experiment with four factors and three levels: glazed hollow bead, sepiolite, air-entraining agent, and cellulose ether. Additionally, a single-factor experiment is conducted to analyze the influence degree of water-solid ratio and these four factors. The experimental results are then verified through SEM (Scanning Electron Microscope) observation. The research findings indicate that glazed hollow beads have the most significant impact on thermal conductivity and compressive strength, while the air-entraining agent exerts the greatest influence on flexural strength. Specifically, when the content of glazed hollow bead is 2%, sepiolite 1%, air-entraining agent 0.6%, and cellulose ether 0.6%, the thermal conductivity can reach a minimum value of 0.0533W/(m·K). On the other hand, when the content of glazed hollow bead is 1%, sepiolite 2%, air-entraining agent 0.4%, and cellulose ether 0.6%, the compressive strength can achieve a maximum value of 2.4 MPa. These findings provide a solid foundation for further exploration into improving the performance of thermal insulation mortar.

Research on fire resistance and economy of basalt fiber insulation mortar

The construction sector has become the most critical source of carbon emissions, but the existing thermal insulation materials such as thermal insulation mortar have obvious limitations, so it is urgent to develop building thermal insulation materials with superior performance and low cost. Aiming at the problem of poor bond strength of foam thermal insulation mortar, this research team selected basalt fiber as admixture to verify the influence of basalt fiber content on its performance and the economic feasibility of thermal insulation mortar. The main finding is that basalt fiber as an additive can obviously improve the crack resistance of thermal insulation mortar. When the content of basalt fiber increases from 0 to 2.5%, the compressive strength of mortar increases at first and then decreases, and the bond strength increases nonlinearly, but the thermal conductivity and dry density also increase. Therefore, the optimal content of basalt fiber is 1.5%. The improvement effect of fire resistance of thermal insulation mortar with 1.5% basalt fiber content is better. After curing for 28 days, the mass loss rate of the sample is reduced by about 11.1% after high temperature, and the relative compressive strength is increased by about 9.71% after high temperature. The raw material cost of the new fireproof thermal insulation mortar improved by basalt fiber is lower, and the cost of the finished product is reduced by 16.98%, 28.18%, 33.05% and 38.96%, respectively, compared with the four types of thermal insulation mortar already used in the market. More importantly, the economic recovery period of the new fireproof and thermal insulation mortar is undoubtedly shorter than that of alternative thermal insulation or energy storage materials, which not only achieves low emission and environmental protection, but also satisfies the economic feasibility.

Crack behavior of expanded polystyrene foam-ceramsite composite thermal insulation mortar

To compensate for the deficiencies of thermal insulation, fire and crack resistances of traditional thermal insulation mortars, this paper prepares expanded polystyrene foam (EPSF)-ceramsites composite thermal insulation mortar (ECTIM) with ceramsite and EPSF particles as insulation aggregates. The effects of fiber content (i.e., P = 0.3%, 0.6%, 0.9%), fiber length (i.e., l = 3 mm, 6 mm, 9 mm) and fiber types (i.e., polypropylene fiber (PF), steel fiber (SF), alkali resistant glass fiber (ARGF)) on crack resistance of the ECTIM were analyzed. The test results demonstrated that the incorporation of fibers could significantly improve crack resistance and delay the cracking of mortar. With the increase of fiber content P, the water loss rate and cracking index decreased to 43.70% and 79.17% of the specimen without fiber. As the fiber length l increased from 0 mm to 9 mm, the water loss rate and cracking index decreased by 41.50% and 77.08%, respectively. Comparatively, the PF could obviously improve the crack resistance of the ECTIM. Based on the experimental research, the microscopic stress mechanism of mortar cracking, as well as the early and late anti-cracking mechanism of the ECTIM were revealed. In addition, considering the effects of fiber content and fiber length, a comprehensive influence coefficient ϖ was introduced, and a formula for conveniently calculating the maximum crack width Wmax of the ECTIM was proposed. The predicted results agreed well with the test data. The thermal insulation mortar prepared in this study could considerably overcome the deficiencies of traditional organic and inorganic thermal insulation mortars, and had excellent thermal insulation, fire and crack resistances. The resource utilization of iron tailings and the introduction of ceramsite reduced the materials cost. The prepared thermal insulation mortar could be used for wall substrate, geothermal heat insulation layer, external wall, internal wall and roof insulation.

Controllable preparation of aerogel/expanded perlite composite and its application in thermal insulation mortar

The extremely low strength and high cost of aerogel limit its applicability in energy-efficient buildings. In this paper, the controllable preparation method of aerogel/expanded perlite (AEP) was developed, and the particle gradation effect on AEP thermal insulation mortar (AEPM) was assessed, which provided an effective way for the application of aerogel and AEP in buildings. The results showed that the acid/base catalysis two-step method was imperative for preparing AEP. It was also found that the pH of SiO2 hydrosol should be controlled within 3.2–3.5, and the corresponding gel time of SiO2 hydrosol was 30–90 min. The impregnation-adsorption process of EP adsorbing SiO2 hydrosol should be completed before the initial viscosity of 3 mPa·s changes. The amount of SiO2 hydrosol adsorbed by EP had a logarithmic relationship with the adsorption time under the adsorption of ambient pressure (AP), whereas its linear relationship with the adsorption pressure under the adsorption of vacuum pressure (VP) was found. The pores of expanded perlite (EP) were filled with well-structured aerogel due to the controlled preparation of AEP. Thus, the AEP bulk density increased by 24%-50% compared with EP. However, the thermal conductivity decreased by 14.6%-31.8%, and the particle strength of AEP was not significantly improved compared with that of EP. AEPM prepared by AEP showed typical characteristics of high strength and low thermal conductivity. The compressive strength of AEPM was 6.5% lower than that of EPM but more than twice that of AERM, while the corresponding water absorption and thermal conductivity were 27.6% and 26.6% lower than EPM. As a new nano-micron porous composite, AEP has great applicability in developing thermal insulation materials, phase change materials, and adsorption materials.

Research on fire resistance of silica fume insulation mortar

Due to the increasingly tight energy supply situation, thermal insulation mortar is more and more widely used in the exterior wall insulation layer of buildings in various countries. However, the existing academic papers have less research on the key properties of thermal insulation mortar such as fire resistance and economic feasibility. Based on the previous research results, this study selected silica fume as an admixture to improve the comprehensive performance of insulation mortar. The goal is to develop a high-performance fireproof insulation mortar. This paper focuses on the fire resistance of the improved insulation mortar. The results show that silica fume mixed into the mortar will play a fine particle filling and hydration gelation cooperation, and the amount of silica fume mixed from 0 to 10% can significantly improve the bond strength and compressive strength of the mortar. For the thermal conductivity and dry density of mortar, there is a certain increase in the range of silica fume dosing from 0 to 4%, while the range of silica fume dosing from 4% to 10% decreases again. Silica fume has a favorable effect on improving the fire resistance of insulating mortar, and the mortar with 10% admixture of silica fume has about 28.30% lower mass loss rate after high temperature and about 14.73% higher relative compressive strength after high temperature after 28 days of maintenance. The final selected optimum admixture of silica fume is 10%, and the best ratio of raw materials is cement: aggregate: water: dispersible emulsion powder: fly ash: diabase rock powder: AOS foaming agent: gelatin: silica fume = 1: 1.67: 2: 0.045: 0.15: 0.225: 0.035: 0.02: 0.138.

Effect of composite polystyrene granular thermal insulation mortar on thermal energy storage of building energy consumption

In order to save energy and reduce building energy consumption, the author pro?posed a study on the impact of composite polystyrene particle thermal insulation mortar on building energy consumption and thermal energy storage, take the ETIRS-C residence as the research object, through simulation calculation under different insulation mortar thickness, analyze the relationship between insulation thickness and energy consumption and thermal environment. According to the simulation calculation of room temperature, horizontally, the thickness of thermal insulation mortar in air conditioning season is not sensitive to the natural room temperature, there is a certain sensitivity to the natural room temperature in the heating season, in the longitudinal direction, the 30 mm thick insulation mortar is the jumping point, and the increase of the thickness of insulation mortar has no obvious effect on the natural room temperature. According to the simulation cal?culation of room energy consumption, the thickness of thermal insulation mortar is about 20 mm, and both heat and cold consumption have achieved good thermal insulation and energy saving effect, further increasing the thickness of thermal insulation mortar will have limited impact on energy consumption, which may be uneconomical and increase the cost and construction difficulty. Therefore, based on the aforementioned results, it can be considered that the thickness of thermal insulation mortar should preferably be controlled within 20-30 mm.

A comprehensive performance evaluation of the cement-based expanded perlite plastering mortar

A single performance evaluation does not cover all the situations encountered in cement-based plastering mortar applications in walls. This paper proposes a comprehensive performance evaluation method for assessing the cement-based plastering mortar by comprehensively considering the physical characteristics, microstructures, thermal performances, mechanical properties and adsorbability of materials. The relative performances of each test item were compared with standards and previous studies, and the calculation equation of the comprehensive performance value was obtained. In this study, the common cement plastering mortar (CM) and lightweight mortar were mixed with expanded and vitrified beads as aggregates mortar (EVBM), wood fibres, sepiolite and expanded perlite-based plastering mortar (WM) and three types of homemade optimized mortars were moulded as testing specimens. The reference material was marked as CM, and the weights of each parameter in the equation were artificially set according to the applied conditions of the building and restricted by the comprehensive performance value of the ideal plastering mortar at the same time. Through the evaluation of the comprehensive performance and the calculation of these mortars from a case setting of weights, the combined mixing of diatomite, sepiolite with fly ash is better than each single material mixed in mortars, and the comprehensive performance value of mortars with a single function is functional, such as thermal insulation mortar. This paper provides an evaluation method for the comprehensive application of cement-based plastering mortar on the wall.

Effect of different strengthening materials on tensile behaviour of plasters and renders

The purpose of strengthened plasters (interior applications) and renders (exterior applications) in this paper is to control cracks at the interface between the main structure and the infill wall rather than strengthen masonry and reinforced concrete structures. Cracks in plasters and renders have caused severe issues that need to be resolved urgently. Cracks affect not only the aesthetics but also the normal use of a building. The presence of cracks changes the perceptions of the owners of a structure, forcing them to question its safety and even take legal action against its developer. Consequently, the present paper discusses the effects of different strengthening materials on the tensile behaviour of plasters and renders, particularly on the first cracking. One test group without strengthening materials and six test groups with strengthening materials were tested under uniaxial tensile loads. Each experimental group included the same six specimens. A glass fibre-reinforced polymer (GFRP) grid, two types of basalt fibre-reinforced polymer (BFRP) grids, and three types of welded wire meshes (WWMs) were selected as the strengthening materials in the tests. Four types of plasters and renders were used: cement mortar, anti-crack mortar, gypsum plaster, and thermal insulation mortar. The crack pattern, stain–stress relationship, first cracking strain, energy dissipation capacity in the uncracked stage, and microstructure were investigated to gain better insight into the tensile behaviour of the plasters and renders. It was found that a strengthening material with a small mesh size resulted in numerous cracks and a narrow crack spacing. The stress–strain curves of the strengthened specimens could be divided into uncracked and cracked stages. The higher slopes in both stages of the strengthened specimens could be attributed to the higher longitudinal strain coefficient, smaller opening size, and larger cross-sectional area of each strand of the strengthening materials. The first cracking strain of the unreinforced specimen was smaller than that of a strengthened specimen. Stronger bond strength between plaster/render and strengthening material, smaller mesh size and greater cross-sectional area of each strand of strengthening material led to the larger first cracking strain. The energy dissipation capacity in the uncracked stage of the strengthened thermal insulation mortar was the least. The energy dissipation capabilities in the uncracked stage of the plasters/renders reinforced with BFRP grid-2 and WWM-3 were the second-highest and highest, respectively. The bond strengths of the GFRP and BFRP grids to the plasters/renders were stronger than those of the WWMs. The bond strengths between the gypsum plaster and the reinforcing materials were the highest, whereas those between the thermal insulation mortar and the strengthening materials were the lowest. Additionally, stress–strain relationships were proposed for the strengthened plasters and renders; the results were found to be in good agreement with the test results.

Performance of alkali-activated cementitious composite mortar used for insulating walls

There are large volumes of fly ash, slag and silica fume produced in the world. The waste disposal to the landfill is problematic and causes many environmental issues. The objective of this work is to demonstrate how fly ash, slag and silica fume can be used to produce alkali-activated cementitious composite mortar (AACCM) used for insulating walls. The combination of both polymers and alkali-activated cementitious material (AACM) made from fly ash, slag powder and silica fume enables a full composite action. The polymers include Methyl Cellulose Ether (MCE), Polyvinyl Alcohol (PA), and Calcium Formate (CF). The thermal insulating aggregates were cemented into insulating mortar under the composite action. The ratio of fly ash, slag powder and silica fume in the AACM is 5:5:1. The experimental results show that the compressive strength, dry density and thermal conductivity of cement-based thermal insulation mortar (TIM) decrease significantly with the increase of MCE content. MCE has an obvious air-entraining effect on cement-based mortar. When the percentages of MCE, PA, and CF are 1%, 1.6% and 1%, the compressive strength, dry density and thermal conductivity of the TIM are 0.50 MPa, 398.7 kg/m3, and 0.0932 w/(m·k) respectively. MCE has a weak air-entraining effect on AACM. When the percentages of MCE, PA, and CF are 3%, 2% and 1%, the compressive strength, dry density and thermal conductivity of the TIM are 0.28 MPa, 328.7 kg/m3, and 0.0775 w/(m·k) respectively. The simulation results of heat transfer performance show AACCM can be used for insulating walls.

Experimental Investigations on Water Absorption and Mechanical Properties of Expanded Perlite Thermal Insulation Mortar Under Accelerated and Natural Aging Conditions

Experimental Investigations on Water Absorption and Mechanical Properties of Expanded Perlite Thermal Insulation Mortar Under Accelerated and Natural Aging Conditions

Effect of thermal insulation components on physical and mechanical properties of plant fibre composite thermal insulation mortar

To improve the resource level of agricultural and forestry waste straws and fallen leaves, straw and fallen leaves fibres were used as organic thermal insulation components (TICs). Vitrified beads and closed-pore expanded perlite were used as inorganic TICs to prepare plant fibre cement-based composite thermal insulation mortar (TIM). The effects of TICs on physical and mechanical properties of TIM were studied by altering the types and contents of TICs. The results show that the fluidity of the TIM decreases with the incorporation of plant fibres in the vitrified bead + expanded perlite TIM. With the addition of wheat straw fibre and straw fibre, the homogeneity of TIM mixture is improved. Plant fibres have the characteristics of lightweight, porosity, water absorption and heat preservation, which increases water absorption and heat retention and a decrease in strength of the TIM. With the incorporation of three plant fibres of leaves, wheat straw and straw, the water absorption of TIM increased by 15.84, 5.47, and 4.54% respectively. At the same time, thermal conductivity decreased by 0.17, 0.19, and 0.20 W/(m.K), respectively, flexural strength decreased by 3.99, 2.63, and 2.44 MPa, and compressive strength decreased by 20.91, 17.13, and 19.25 MPa, respectively. After the expanded perlite and vitrified microbeads are modified with pure acrylic emulsion, the polymer film retains more pores inside the fibres, enhances the interface bonding with the cement-based material, which is helpful to improve the thermal insulation properties and strength of the TIM.

Experimental Study on Composite Phase Change Thermal Insulation Mortar

The insulation wall provides suitable heat for winter production of solar greenhouse. A thermal insulation mortar containing paraffin/expanded perlite composite phase change material based on desulfurized gypsum was studied as an inner insulation mortar to improve heat preservation and storage/exothermic capacities in solar greenhouse walls. Results showed that the ideal mass ratio of paraffin and expanded perlite was 60:40. The phase change temperature of the paraffin/expanded perlite composite particles was 25.3 °C, and the latent heat was 122.3 kJ/kg. The ideal mass ratio of this composite phase change material and desulfurized gypsum was 1:3. The ideal mixing amounts of dispersible polymer powder, redispersible latex powder, citric acid, hydroxypropyl methyl cellulose ether, and polypropylene fiber were 2%, 0.15%, 0.5%, and 0.5% of desulfurized gypsum content, respectively. The prepared composite phase change thermal insulation mortar had a dry density of 363 kg/m3, a compressive strength of 0.73 MPa, a softening coefficient of 0.65, a coefficient of thermal conductivity of 0.076 W/m·K-1, a heat capacity of 1.35×103 J/kg·°C-1, a heat storage coefficient of 11.65 W/m2·K-1, a phase change temperature of 25.6 °C, and a phase change latent heat of 89.8 kJ/kg. The phase change temperature and the phase change latent heat were suitable for solar greenhouse production.

Analysis of new inorganic exterior insulation materials and thermal energy storage

In order to reduce the energy efficiency of the construction industry and improve the building safety, in this research, a new type of inorganic insulation material ? vitreous bead insulation mortar is studied and its properties are analyzed. Quantitative method is used to analyze the influence of glass bead mixing amount, cellulose ether mixing amount and redispersible emulsion powder mixing amount on the consistency, water retention rate, dry density, softening coefficient and compressive strength of glass bead insulation mortar. The effect of different raw materials allocation on the thermal conductivity of vitrified microbeads thermal insulation mortar is explored. The results show that the performance of insulation mortar decreases significantly with the increase of glass bubbles. With the increase of cellulose ether content, the consistency and compressive strength of insulation mortar first increased and then decreased, the water retention rate increased significantly, but the dry density decreased significantly. With the increase of the content of redispersible emulsion powder, the consistency and compressive strength of insulation mortar first increased and then decreased, but the dry density decreased gradually. Glass bubbles and fly ash parameters are the main factors that affect the thermal conductivity of thermal insulation mortar, and their thermal conductivity decreases with the increase of the proportion of air-entraining agent. As a result, the performance of vitreous microbeads thermal insulation mortar will change to a certain extent with the different proportion of raw materials, which provides data support for the preparation and application of inorganic external wall thermal insulation materials.

Study on EPS thermal insulation mortar prepared by magnesium oxychloride cement

In this paper, a composite thermal insulation mortar was prepared with magnesium oxychloride cement and polystyrene (EPS) particles. The influence of EPS particles content on the mechanical strength, density and thermal conductivity of composite thermal insulation mortar was studied. Also, the effect of fly ash on the density and thermal conductivity of the mortar was researched. It was shown that: (1) Generally, EPS particles could reduce the compressive strength, flexural strength, density and thermal conductivity of the mortar. The 28 days compressive strength and 28 days flexural strength decreased by 93.3 % and 81.3 % respectively, with the content of EPS particles from 0 % to 0.486 %. Also the density of the mortar was reduced from 2043 g/dm3 to 805 g/dm3, and the thermal conductivity was fell from 0.4093 W/(m·K) to 0.2191 W/(m·K). (2) Small amounts (less than 5.487 %) of fly ash could increase the density and thermal conductivity. However, when the content of fly ash was more than 5.487 %, the density and thermal conductivity of thermal insulation mortar were significantly reduced.

Preparation of EPS-Based Thermal Insulation Mortar with Improved Thermal and Mechanical Properties

A new method of preparing expandable polystyrene (EPS) insulation mortar is presented in this work. It consists of using two polymer emulsion adhesives (POEA): commercial water-soluble polyvinyl formaldehyde adhesive (PFA) and polyvinyl acetate emulsion (PAE). The effects of EPS dosage, polymer emulsion adhesive, air-entraining agent, and fly ash content on the performance of EPS mortar were investigated. The workability, mechanical properties, thermal conductivity, water absorption, and softness coefficient of the prepared samples were experimentally studied. The experimental results showed that high-performance EPS thermal insulation mortar can be prepared by limiting the EPS volume fraction to 80%–82%, air content to around 20%, and fly ash content to 20%. The bonding strength and flexural strength were improved as polyvinyl acetate emulsion was added. Also, the drying shrinkage and thermal conductivity were improved with the addition of fly ash.

Effect of Active Admixture and Air Entraining Agent on Frost Resistance of Volcanic Scoria Thermal Insulation Plastering Mortar

The effects of fly ash, slag powder, diatomite and air entraining agent on the mechanical properties and freeze-thaw resistance of volcanic scoria thermal insulation plastering mortar were studied by orthogonal test. The test results showed that the thermal insulation plastering mortar achieves the best performance when the replacement rate of fly ash was 20%, the substitution rate of slag micropowder and diatomite is 10%, and the amount of air entraining agent is 0.1%. Compared with the ordinary thermal insulation plastering mortar, the 28d compressive strength is increased by 17.8%, the strength loss rate was reduced by 34.5% and the quality loss rate was reduced by 43.3%. Observing the microstructure of the thermal insulation plastering mortar by SEM, active admixture is beneficial to improving the structure of the hydration product and improving the compactness of the thermal insulation mortar.

Study on Building Energy Consumption Performance of Composite Polystyrene Granule Thermal Insulation Mortar

In order to solve the problem of building energy consumption, the hygroscopicity, thermal conductivity and transfer properties of composite polystyrene particle thermal insulation mortar are analyzed. According to the commonly used external thermal insulation structure and its thermophysical characteristics in hot summer and cold winter zone, the test is carried out. The thermal conductivity function is applied to the simplified model of DeST thermal environment simulation. The variation of heat and moisture transfer to building energy consumption is analyzed. The results show that the energy consumption of simulated buildings can reach 13.25% of the annual electricity consumption of building heating. Therefore, the heat and moisture transfer characteristics of materials affect the thermal conductivity and thermal insulation performance of building envelope. It is an effective way to decrease the building energy consumption by using the thermal conductivity coefficient of various materials as a measure.

Effect of fly ash on drying shrinkage of thermal insulation mortar with glazed hollow beads

Drying shrinkage of thermal insulation mortar with glazed hollow beads was measured by a vertical length comparator, and the influences of fly ash with different contents (0, 18%, 36%, and 54% were used) on the long-term drying shrinkage were discussed. The mass loss was measured by the weighting method and the pore structure was characterized using three different methods, including the light microscopy, the mercury intrusion porosimetry (MIP), and the nitrogen adsorption/desorption (NAD) experiments, and the correlations among them were researched. The results show that drying shrinkage process of thermal insulation mortar includes three steps with increasing curing time: the acceleration period (before 7 d), the deceleration period (7-365 d), and the metastable period (after 365 d). Drying shrinkage in the first stage (7 d before) increases quickly owing to the fast water loss, and its development in the last two stages is attributed to the increment of the pore volume of mortar with the radius below 50 nm, especially the increment of the pore volume fraction of the pore radius within the size range between 7.3 nm and 12.3 nm. There is no change in the drying shrinkage development trend of mortar with fly ash addition, and three steps in the service life, but fly ash addition in the mortar restrains its value. There is a linear relationship between the drying shrinkage and fly ash content, which means that drying shrinkage reduces with fly ash addition.