بررسي تكنولوژي بتن پودري واكنشي ﴿RPC﴾ و اثر توام ميكرو سيليس و نانو سيليس بر آن

چكيده انگليسي :

Technological study of Reactive Powder Concrete RPC and Combined Effect of Nano SiO2 and Silica fume on it Mojtaba Rostami Niko rostami mojtaba@yahoo com April 2012 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Davood Mostofinejad dmostofi@cc iut ac irAbstract One of the materials used to build structures is concrete Concrete is also one to the up to date topicalwhich researchers are using innovative ways to remove its negative aspects and Improve its capabilities Thusin the last few decades new types of concrete has been produced and Improved One type of concrete firstKnown world wide in 90 s is RPC This is generally achieved by a micro structural engineering approach including elimination of the coarseaggregates in order to increase the homogeneity of the material increased compactness through optimizationof the grading reducing the water to cementitious material ratio lowering the CaO SiO2 ratio byintroducing silica components improvement of the microstructure by pressure casting with heat treatmentcuring and further addition of steel bers to improve ductility Original reactive powder concrete in theform of a superplasticized cement mixture with silica fume steel bers and ground ne quartz Nowadays RPC is regarded as a promising material for special prestressed and precast concrete membersincluding those within industrial and nuclear waste storage facilities RPC has a very high compressive strength To create this type of concrete researchers use different mixdesigns since no code non a proper mix design is available Most of the collected strengths which their mixdesign was available were collected using steel fibers which were in the range of 200 MPa After reviewingmany papers a certain mix design leading to compressive strength of RPC without steel fiber exceeding 200MPa has not been found One of the proper pozzolanic materials Introduced these days is Nano SiO2 Nano SiO2 had not been used in RPC yet Thus some Nano SiO2 was added to RPC The only aim was to increasethe compressive strength of RPC The main aim in the presented paper is reaching to proper mix design for aRPC which can gain at least 200 MPa compressive strength without using steel fibers and concrete pastecompaction Effect of amount of Materials different curing ways and addition of Nano SiO2 on thecompressive strength of RPC has been analyzed In the presented research different steps were used so that in each step a certain parameter is analyzed andImproved In each step limited number of mix design is Introduced and amount and proper ratio of materialsis gained Then in the next steps new mix designs are Introduced acknowledging the previous results gainedfrom previous steps In the presented paper a base mixture desing whit 28 days standard compressive strengthequal to 85 MPa is used Whit change in mix design and the way of curing it RPC with compressivestrength of 233 MPa was produced Curing leding to this strength was autoclave along with temperature of220 0C heating operation An approximately 1100 kg m3 cement was used to produce this concrete In theend effect of replacing silica fume with Nano SiO2 on the compressive strength of RPC has been analyzed Addition of nano SiO2 did not have a positive effect on the RPC compressive strength and lead to reductionof RPC strength Keywords Reactive Powder Concrete RPC compressive strength Nano SiO2 steel fiber 200 MPa autoclave

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بررسي تكنولوژي بتن پودري واكنشي ﴿RPC﴾ و اثر توام ميكرو سيليس و نانو سيليس بر آن

مقاومت فشاري , مواد پوزولاني , الياف فولادي , MPa200 , عمل آوري