The aim of this study was to create a foaming agent and then evaluate its performance.This foaming agent is made up of Sodium lauryl sulfate,Ethanol,Lauryl alcohol and Water.On aeration,the diluted foaming solution pr...The aim of this study was to create a foaming agent and then evaluate its performance.This foaming agent is made up of Sodium lauryl sulfate,Ethanol,Lauryl alcohol and Water.On aeration,the diluted foaming solution produces a stable foam whose properties,density,capacity and drainage were studied.The compressive strength,water absorption and density of foamed concrete were also studied.Test results show that the initial foam density is 104kg/m3 at an optimum dilution ratio of 1:40.Foamed concrete’s density can vary from 450kg/m3 to 1 950bkg/m3 and its compressive strength is in0.5~23 MPa.Compressive strength test results of this foaming agent are higher than those produced with EABASSOC foaming agent.According to ASTM 869-91,this chemical composition qualifies to be used as a foaming agent.展开更多
The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and lo...The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and low ductility was introduced.And it was made as filling material of reserved deformation layer between the first lining and the second lining used in large-span soft rock tunnel.The effect of the new type of foam concrete was simulated as filling material of reserved deformation layer using numerical simulation.Through the comparison with the common large-span soft rock tunnel,the vault settlement and surrounding convergence are reduced by about 61% and 45%,respectively,after creep of 100 a.And in the second lining,the plastic zone reduces apparently and the maximum equivalent plastic strain decreases relatively.So,it can be found that the application of the new type of foam concrete as the filling material of reserved deformation layer can relieve the excessive force in second lining induced by rock creep,reduce its deformation and improve the stability of tunnel.展开更多
Sirnak City and the surrounding areas are on steeper slopes. There are sliding large land masses or rocks. Underground water and harsh climatic conditions contain high risk hazard areas in urban living site with highe...Sirnak City and the surrounding areas are on steeper slopes. There are sliding large land masses or rocks. Underground water and harsh climatic conditions contain high risk hazard areas in urban living site with higher population density. In order to eliminate landslides and related events, significant precautions should be taken. The mapping of landslide risk may ease to take precautions. Even the application of landfill rock may reduce water content of soil. In this research, fly ash and Mine Waste shale stone were used with low density foam concrete. Waste mixture at certain proportions decreased cement use. Shale stone as fine aggregate instead of fly ash in specific proportions improved mechanical strength and porosity. Hence landslide hazardous area could be safer for urban living.展开更多
Extrudability is one of the most critical factors when designing three-dimensional printable foam concrete.The extrusion process likely affects the foam stability which necessitates the investigation into surfactant p...Extrudability is one of the most critical factors when designing three-dimensional printable foam concrete.The extrusion process likely affects the foam stability which necessitates the investigation into surfactant properties particularly for concrete mixes with high foam contents.Although many studies have been conducted on traditional foam concrete in this context,studies on three-dimensional printed foam concrete are scarce.To address this research gap,the effects of surfactant characteristics on the stability,extrudability,and buildability of three-dimensional printed foam concrete mixes with two design densities(1000 and 1300 kg/m^(3))using two different surfactants and stabilizers(synthetic-based sodium lauryl sulfate stabilized with carboxymethyl cellulose sodium salt,and natural-based hingot surfactant stabilized with xanthan gum)were investigated in this study.Fresh density tests were conducted before and after the extrusion to determine stability of the foam concrete.The results were then correlated with surfactant qualities,such as viscosity and surface tension,to understand the importance of key parameters in three-dimensional printing of foam concrete.Based on the experimental results,surfactant solu1tion with viscosity exceeding 5 m Pa·s and surface tension lower than 31 mN/m was recommended to yield stable three-dimensional printable foam concrete mixes.Nevertheless,the volume of foam in the mix significantly affected the printability characteristics.Unlike traditional foam concrete,the variation in the stabilizer concentration and density of concrete were found to have insignificant effect on the fresh-state-characteristics(slump,slump flow,and static yield stress)and air void microstructure of the stable mixes.展开更多
Laboratory experiments were conducted to determine the effect of foaming agent(egg white(EW)),foam stabilizer(carboxyl methyl cellulose(CMC))and whipping time on drying rate and quality of tomato(Lycopersicon esculent...Laboratory experiments were conducted to determine the effect of foaming agent(egg white(EW)),foam stabilizer(carboxyl methyl cellulose(CMC))and whipping time on drying rate and quality of tomato(Lycopersicon esculentus)paste dried under air oven,microwave oven and mechanical dryer.A 43 factorial experiment in Randomized Complete Block Design(RCBD)was used to study the effect of four levels each of foaming agent(5%,10%,15%and 20%EW),foam stabilizer(0.15%,0.30%,0.45%and 0.60%CMC)and whipping time(3,5,7 and 9 min)on the drying rate and the quality of foam-mat dried tomato powder in the three drying equipment.Each trial was performed in triplicates making a total number of 576 samples that were individually tested and measured.25 g sample of the paste was dried to a moisture content of 7.60%(wb)for 8 h in mechanical dryer and oven dryer at temperatures of 55◦C and 50◦C,respectively,and 10 min in microwave oven at 540 W.Data obtained from the experiments were statistically analyzed using the analysis of variance(ANOVA)while the Duncan’s Multiple Range Test was used to compare the means.Results showed that the drying rate increased with increase in foaming agent,foam stabilizer and whipping with minimum values of 9.21 g/h obtained in mechanical dryer,9.31 g/h in air oven and 8.05 g/h in microwave oven.Increase in foaming agent,foam stabilizer and whipping time did not cause any adverse effect on vitamin C,ash,protein,fat,carbohydrate,crude fiber contents of the samples.Samples reached a stable moisture content of 7.60%(wb)in less than 8 h in mechanical dryer and air and less than 10 min in microwave oven.The results of the study showed that EW,CMC and whipping time influenced the drying rate and quality of foam-mat dried tomato powder.展开更多
In order to prepare the polyethylene materials with controlling properties,we developed two kinds of controllable cross-linking polyethylene foaming system.2,5-dimethyl-2,5-bis (tert-butyl peroxy) hexane was used as c...In order to prepare the polyethylene materials with controlling properties,we developed two kinds of controllable cross-linking polyethylene foaming system.2,5-dimethyl-2,5-bis (tert-butyl peroxy) hexane was used as cross-linking agent and TEMPO as cross-linking inhibitor,azodicarbonamide (AC) was used as foaming agent and citric acid as foaming promoter.The density,expansion ratio,cellular structure and mechanical property of these two kinds of controllable materials were studied.Experimental results show that,properties of these two kinds of materials appear similar trend:cellular size and expansion ratio are enlarged with the amount of cross-linking inhibitor or foaming promoter increasing,while density and mechanical strength appear decreasing trend.Through comparing those two material systems’ properties,cross-linking polyethelene foaming system with citric acid as foaming promoter has better properties.展开更多
Living in a habitat with comfort is requested by all. Cinder block bricks have poor thermal properties, leading people to use fan heaters and air conditioners to regain comfort. To overcome this problem of thermal dis...Living in a habitat with comfort is requested by all. Cinder block bricks have poor thermal properties, leading people to use fan heaters and air conditioners to regain comfort. To overcome this problem of thermal discomfort in buildings, we used lightweight concrete such as foamed concrete which is a material that has improved thermal properties for thermal comfort. In addition, this material was compared with local materials used for the construction of buildings such as BTC, adobe and BLT mixed with binders. The results showed that foamed concrete is a material that has good thermal and mechanical properties compared to local materials mixed with binders. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m<sup>3</sup>. It has a thermal resistance of 0.4 m<sup>2</sup>·K/W for a thickness of 20 cm. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m3</sup>. It has a thermal resistance of 0.4 m2</sup>·K/W for a thickness of 20 cm. For sunshine on a daily cycle equal to 12 hours, the characteristic thickness achieved by this material is 7.29 cm. It also has a shallow depth of heat diffusion having a lower thickness than other materials. This shows that foamed concrete is a promising material for the construction of buildings.展开更多
文摘The aim of this study was to create a foaming agent and then evaluate its performance.This foaming agent is made up of Sodium lauryl sulfate,Ethanol,Lauryl alcohol and Water.On aeration,the diluted foaming solution produces a stable foam whose properties,density,capacity and drainage were studied.The compressive strength,water absorption and density of foamed concrete were also studied.Test results show that the initial foam density is 104kg/m3 at an optimum dilution ratio of 1:40.Foamed concrete’s density can vary from 450kg/m3 to 1 950bkg/m3 and its compressive strength is in0.5~23 MPa.Compressive strength test results of this foaming agent are higher than those produced with EABASSOC foaming agent.According to ASTM 869-91,this chemical composition qualifies to be used as a foaming agent.
基金Projects(41072238,51009133)supported by the National Natural Science Foundation of China
文摘The long-term stability of large-span soft rock tunnel is influenced greatly by the creep effect of surrounding rock.The development of a new type of foam concrete which has the property of high compressibility and low ductility was introduced.And it was made as filling material of reserved deformation layer between the first lining and the second lining used in large-span soft rock tunnel.The effect of the new type of foam concrete was simulated as filling material of reserved deformation layer using numerical simulation.Through the comparison with the common large-span soft rock tunnel,the vault settlement and surrounding convergence are reduced by about 61% and 45%,respectively,after creep of 100 a.And in the second lining,the plastic zone reduces apparently and the maximum equivalent plastic strain decreases relatively.So,it can be found that the application of the new type of foam concrete as the filling material of reserved deformation layer can relieve the excessive force in second lining induced by rock creep,reduce its deformation and improve the stability of tunnel.
文摘Sirnak City and the surrounding areas are on steeper slopes. There are sliding large land masses or rocks. Underground water and harsh climatic conditions contain high risk hazard areas in urban living site with higher population density. In order to eliminate landslides and related events, significant precautions should be taken. The mapping of landslide risk may ease to take precautions. Even the application of landfill rock may reduce water content of soil. In this research, fly ash and Mine Waste shale stone were used with low density foam concrete. Waste mixture at certain proportions decreased cement use. Shale stone as fine aggregate instead of fly ash in specific proportions improved mechanical strength and porosity. Hence landslide hazardous area could be safer for urban living.
基金The authors gratefully acknowledge the support from the Department of Civil and Mechanical Engineering,Indian Institute of Technology Guwahati,India.
文摘Extrudability is one of the most critical factors when designing three-dimensional printable foam concrete.The extrusion process likely affects the foam stability which necessitates the investigation into surfactant properties particularly for concrete mixes with high foam contents.Although many studies have been conducted on traditional foam concrete in this context,studies on three-dimensional printed foam concrete are scarce.To address this research gap,the effects of surfactant characteristics on the stability,extrudability,and buildability of three-dimensional printed foam concrete mixes with two design densities(1000 and 1300 kg/m^(3))using two different surfactants and stabilizers(synthetic-based sodium lauryl sulfate stabilized with carboxymethyl cellulose sodium salt,and natural-based hingot surfactant stabilized with xanthan gum)were investigated in this study.Fresh density tests were conducted before and after the extrusion to determine stability of the foam concrete.The results were then correlated with surfactant qualities,such as viscosity and surface tension,to understand the importance of key parameters in three-dimensional printing of foam concrete.Based on the experimental results,surfactant solu1tion with viscosity exceeding 5 m Pa·s and surface tension lower than 31 mN/m was recommended to yield stable three-dimensional printable foam concrete mixes.Nevertheless,the volume of foam in the mix significantly affected the printability characteristics.Unlike traditional foam concrete,the variation in the stabilizer concentration and density of concrete were found to have insignificant effect on the fresh-state-characteristics(slump,slump flow,and static yield stress)and air void microstructure of the stable mixes.
文摘Laboratory experiments were conducted to determine the effect of foaming agent(egg white(EW)),foam stabilizer(carboxyl methyl cellulose(CMC))and whipping time on drying rate and quality of tomato(Lycopersicon esculentus)paste dried under air oven,microwave oven and mechanical dryer.A 43 factorial experiment in Randomized Complete Block Design(RCBD)was used to study the effect of four levels each of foaming agent(5%,10%,15%and 20%EW),foam stabilizer(0.15%,0.30%,0.45%and 0.60%CMC)and whipping time(3,5,7 and 9 min)on the drying rate and the quality of foam-mat dried tomato powder in the three drying equipment.Each trial was performed in triplicates making a total number of 576 samples that were individually tested and measured.25 g sample of the paste was dried to a moisture content of 7.60%(wb)for 8 h in mechanical dryer and oven dryer at temperatures of 55◦C and 50◦C,respectively,and 10 min in microwave oven at 540 W.Data obtained from the experiments were statistically analyzed using the analysis of variance(ANOVA)while the Duncan’s Multiple Range Test was used to compare the means.Results showed that the drying rate increased with increase in foaming agent,foam stabilizer and whipping with minimum values of 9.21 g/h obtained in mechanical dryer,9.31 g/h in air oven and 8.05 g/h in microwave oven.Increase in foaming agent,foam stabilizer and whipping time did not cause any adverse effect on vitamin C,ash,protein,fat,carbohydrate,crude fiber contents of the samples.Samples reached a stable moisture content of 7.60%(wb)in less than 8 h in mechanical dryer and air and less than 10 min in microwave oven.The results of the study showed that EW,CMC and whipping time influenced the drying rate and quality of foam-mat dried tomato powder.
基金Funded by National Natural Science Foundation of China (No.21975108)Fundamental Research Funds for the Central Universities of China (No.JUSRP121033)。
文摘In order to prepare the polyethylene materials with controlling properties,we developed two kinds of controllable cross-linking polyethylene foaming system.2,5-dimethyl-2,5-bis (tert-butyl peroxy) hexane was used as cross-linking agent and TEMPO as cross-linking inhibitor,azodicarbonamide (AC) was used as foaming agent and citric acid as foaming promoter.The density,expansion ratio,cellular structure and mechanical property of these two kinds of controllable materials were studied.Experimental results show that,properties of these two kinds of materials appear similar trend:cellular size and expansion ratio are enlarged with the amount of cross-linking inhibitor or foaming promoter increasing,while density and mechanical strength appear decreasing trend.Through comparing those two material systems’ properties,cross-linking polyethelene foaming system with citric acid as foaming promoter has better properties.
文摘Living in a habitat with comfort is requested by all. Cinder block bricks have poor thermal properties, leading people to use fan heaters and air conditioners to regain comfort. To overcome this problem of thermal discomfort in buildings, we used lightweight concrete such as foamed concrete which is a material that has improved thermal properties for thermal comfort. In addition, this material was compared with local materials used for the construction of buildings such as BTC, adobe and BLT mixed with binders. The results showed that foamed concrete is a material that has good thermal and mechanical properties compared to local materials mixed with binders. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m<sup>3</sup>. It has a thermal resistance of 0.4 m<sup>2</sup>·K/W for a thickness of 20 cm. The foamed concrete having acceptable thermo-mechanical properties was that having a density of 930 kg/m3</sup>. It has a thermal resistance of 0.4 m2</sup>·K/W for a thickness of 20 cm. For sunshine on a daily cycle equal to 12 hours, the characteristic thickness achieved by this material is 7.29 cm. It also has a shallow depth of heat diffusion having a lower thickness than other materials. This shows that foamed concrete is a promising material for the construction of buildings.