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Research On The Application Of Phosphorous Slag In The Cement-based Grouting Mortar

Posted on:2013-09-25Degree:MasterType:Thesis
Country:ChinaCandidate:D J ZhouFull Text:PDF
GTID:2232330362473983Subject:Materials Science and Engineering
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Phosphorus slag is a kind of industrial residue which is produced in yellowphosphorus industry through electric furnace process. Large amounts of phosphorousslag is produced and results in the pollution of environment. Cement-basedgrouting mortar has high fluidity, high early strength, high strength, and micro-expansion properties, widely used in anchorage, reinforcement and repair field. The useof phosphorus slag in grouting mortar not only can save cement, which reduces the cost,but also lead to large-scale reduction in phosphorus slag piled up, which achieves thepurpose of protecting the environment and economic benefits.This thesis reports that through the analysis of the phosphorus slag, preparationparameters, admixtures effect on properties of mortar grouting, grouting mortar basedmixture ratio was determined, and by the orthogonal experiment that further optimizedthe mixture ratio. Hydration hardening mechanism on cement-phosphorus slag-expansive agent composite cementitious material was analyzed by modern analyticaltechnology. The research results can be concluded as following:1) Phosphorus slag, as an admixture mixed into the grouting mortar, with theincrease of dosage, extended the initial setting time of mortar, increased mobility, whilethe early strength decreased obviously. Considering the requirements of the groutingmortar on the early strength, phosphorus slag content should not be more than30%.2) Cement sand ratio on the grouting mortar had little effect on strength, but asignificant effect on mobility. With the cement sand ratio decreased (sand contentincrease), the fluidity of the grouting mortar decreased rapidly.When cement sand ratioranges in1/1~1/1.6, grouting mortar has good mobility with low bleeding rate.3) Incorporation of polycarboxylic water reducing agent or sulphamate seriessuperplasticizer, brought little loss in grouting mortar fluidity. Considering the groutingmortar mobility, strength development and bleeding rate, the polycarboxylic waterreducing agent’s optimal dosage range should be controlled at about1%, sulphamateseries superplasticizer dosage range should be1.2%~1.5%. Triethanolamine, to someextent, can improve the early strength of mortar, with little effect on mortar fluidity. Thesuitable dosage range is0.04%~0.05%. With silicone defoamer dosage increaseing, theliquidity of mortar become better, but if the amount was excessive, the viscosity of themortar decreased, and a certain degree of stratification appeared. The optimal dosage range of0.2%~0.6%; Cellulose ethers could significantly improve the viscosity ofmortar, and meliorate the bleeding of mortar, but had bigger effect on the strength ofmortar development, the optimal dosage was0.025%~0.05%.4) Expansive agent is an important material to ensure expansion of the groutingmortar.With the increase of dosage of expansive agent, mortar bleeding rate decreased,fluidity reduced, with fluidity loss increasing and the initial setting time shortening;mortar strength, viscosity, vertical limited expansion ratio and the bond strength increased,the optimum mix amount of expansive agent was in the range of6%~8%.5) By orthogonal test, grouting mortar mixture ratio was optimized as follows:portland cement was69%, phosphorous slag25%, expansive agent6%, polycarboxylatesuperplasticizer1%, defoaming agen0.4%, cellulose ether0.025%, water cement ratio0.26, cement sand ratio1/1. According to the optimization of mixture ratio, preparationof grouting mortar performance met the building materials industry standards of"cement based grouting material"(JC/T896-2005), and the grouting mortar had goodeconomic benefits.6) The hydration heat experiment, XRD, DSC/TG, SEM and pore structure analysisshowed: Cement-phosphorus slag-expansion agent composite cementitious materialhave less hydration heat, low peak of heat of hydration, withe faster early hydration,less initial defects, expansion or no shrinkage, late secondary pozzolanic reaction madethe structure more compact; composite cementitious material have a lower average poresize and the most probable pore size, fine pore size distribution. The compositecementitious material performed excellent, suitable for preparing grouting mortar.
Keywords/Search Tags:phosphorous slag, grouting mortar, expansive agent, orthogonal test, hydration heat
PDF Full Text Request
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