Preliminary Study On The Preparation Of Foamed Concrete Harbouring The Modified Sugarcane Leaf Fiber

Accordingly,11.697 million tons of sugarcane leaf were produced during 2015-2016 in China but not effectively utilized.In this work,we mixed the cheap and modified sugarcane leaf fiber with the foaming agents to improve foaming properties,employing the fiber's effect of supporting the structure.Moreover,we also improved foamed concrete's properties including slurry sedimentation rate,compressive strength.This not only solved the problem of pollution resulting from burning of the sugarcane leaf,but also expanded its comprehensive utilization method.The lignin existing in plant fibers can hamper the cement solidification,and mositure of fiber is bad for improving the performance of the foaming agents.Alkali treatment can remove most ligin of fiber,but the mechanical properties of the fiber are decreased and the problem of water existing in fiber keeps unsolved.Therefore,it needs to be modified.Then,adding the modified sugarcane leaf fiber into the foaming agents to produce the foamed concrete.Finally,we analyzes the effect of the modified sugarcane leaf fiber to the performance of foamed concrete.The main results were as follows:1.The analizes of mainly component in dry sugarcane indicated that the dry sugarcane leaf includes 47.31%cellulose,23.06%hemicellulose,17.16%lignin,and 9.16%ash.This is almost consistent with the previous study.Sugarcane leaf includes nearly 50%cellulose,so it has a high economic benefit to this study.2.NaOH and H2O2 mixed solution can dissolve ligin of sugarcane leaf.Using the cellulose content as the index of evaluation and the NaOH quality percentage,H2O2 content percentage,ratio of solid to liquid and reaction time as factors,designing four factors and three levels orthogonal test to study removing ligin process at room temperature.After dissolving lignin gained High Content Fiber Sugarcane Leaf(HCFSL).The best process parameters were as follows:NaOH quality percentage was 20%,H2O2 content percentage was 0.6%,solid to liquid was 1:20 and reaction time was 8 h.Under this condition of the process,content of cellulose of sugarcane leaf was 75.94%,and the results showed good reproducibility.3.Through the screening of the modified methods and confirming the adding amount,the 10%Gelatin Film Sugarcane Leaf Fiber(GFSLF)displayed the best effect on improving the performance of foaming agents.Concretely,multiple of performed foam increased by 30.37%,1 hour settling distance decreased no significant(<5%),1 hour water secretion decreased by 6.26%,foam half time increased by 28.98%,foam time increased by 73.73%,foaming time decreased by 41.78%.4.Using electron microscopic,we observe those sugarcane leaf fibers.It showed that GFSLF had fewer branches and more smooth of film than other modified fiber.The fiber was coated with gelatin film to make its mechanical performance improved.The gelatin film was thick,and the residual lignin was not easy to be dissolved.5.Optimization of process for preparation of GFSLF by the four factors quadratic regression orthogonal rotation combination design(full implementatio),and established preferably fitting quadratic regression orthogonal model about multiple of performed foam(Y1),1 hour settling distance(Y2),1 hour water secretion(Y3).Xi was the fiber length,X2 was the gelatin concentration,X3 was the treatment time,X4 was the formaldehyde content.The optimum process parameters of GFSLF were as follows:fiber length was 7 mesh,gelatin concentration was 13%,treatment time was 6.5 h,formaldehyde content was 1.4%.6.The comparition of foamed concrete's properties between foamed concrete adding GFSLF and traditional foamed concrete showed that the quality of adding GFSLF has been improved.Furthermore,slurry sedimentation rate decreased by 58.92%,compressive strength increased by 50.86%,thermal conductivity decreased by 10.97%,dry density decreased by 9.84%,water absorption decreased by 6.80%.According to the standard of"JG/T 266-2011 foamed concrete",we can learn that the compressive strength reaches C5 grade,the dry density reaches A08 grade,the water absorption reaches W10 grade.7.The comparition of foamed concrete's pore structure between foamed concrete adding GFSLF and traditional foamed concrete showed that BJH surface area increased by 11.11%,BJH pore volume increased by 11.55%,BJH pore size decreased by 44.92%.The incorporation of GFSLF can effectively improve the pore structure of foam concrete.