【摘要】：活性粉末混凝土(Reactive Powder Concrete簡稱RPC),是一種新型的超高性能的水泥基復合材料,它是由水泥、級配石英細砂、石英粉、硅灰、超塑化劑和鋼纖維等組成,在凝結(jié)、硬化過程中可采取適當?shù)某尚宛B(yǎng)護工藝,如加壓、加熱而獲得。與普通混凝土相比RPC具有高強度、高韌性、高耐久性、體積穩(wěn)定性良好等優(yōu)點,但RPC中的石英砂、硅灰、鋼纖維都是價格昂貴的材料,其中鋼纖維價格占整個RPC造價的50%左右,在當前技術(shù)領(lǐng)域仍未找到一種更為廉價的纖維材料代替鋼纖維。因此,在RPC配合比設(shè)計過程中,優(yōu)化配合比設(shè)計,最大限度地減少鋼纖維用量是降低RPC成本的有效途徑,對RPC的推廣及應用有著十分重要的意義。 本文試驗研究了RPC力學性能的影響因素,其中包括水膠比、硅灰摻量、硅灰品質(zhì)、硅灰狀態(tài)、粉煤灰和礦粉摻量、鋼纖維摻量、石英砂級配等,當膠凝材料為水泥、礦粉、硅灰,最低鋼纖維體積摻量為1.2%,石英砂級配采用粗、中、細三種級配,外加劑為膠凝材料的2%時,成功配制出力學性能滿足要求的RPC,其中配制出的RPC抗壓強度可達到142.3MPa,抗折強度可達到19.0MPa.彈性模量可達到49.0GPa。 本文還通過電通量法、快速凍融法研究了RPC的抗氯離子滲透和抗凍融破壞的能力。試驗結(jié)果表明：當?shù)V粉替代水泥用量15%,鋼纖維體積摻量為1.2%時,6h通過此RPC試件的電量為25.7C,600次凍融循環(huán)后RPC的質(zhì)量損失4.0%,相對動彈性模量為74.6%,低于標準中關(guān)于試件的質(zhì)量損失率達到5%或相對動彈性模量下降至60%以下的要求,說明該配比配制出的RPC具有優(yōu)異的抗?jié)B性和抗凍性。確定最終配合比為水泥：礦粉：硅灰：石英砂：鋼纖維=1：0.18：0.29：1.53：0.15,水膠比為0.175,減水劑為膠凝材料的2.0%。 本文通過進一步的微觀試驗,進行RPC具有高強度、高耐久性的機理分析。試驗表明：RPC密實度高,內(nèi)部缺陷少,孔隙率低,易腐蝕的組分含量低等特點,使得RPC具有較高的強度和耐久性。 除了RPC性能滿足要求,本問還針對RPC在實際生產(chǎn)過程中遇到的下料口堵塞分料機,蓋板表面有白色痕跡和墊塊痕跡,色差不均,鋼纖維在表面顯現(xiàn)等問題進行分析研究,通過調(diào)試生產(chǎn)設(shè)備、改進生產(chǎn)工藝、調(diào)整生產(chǎn)配合比等方法,使得RPC的生產(chǎn)能夠順利進行。
[Abstract]:Reactive powder concrete (Reactive Powder Concrete) is a new type of ultra-high performance cement-based composites, which is composed of cement, graded quartz fine sand, quartz powder, silica fume, superplasticizer and steel fiber. Appropriate molding and curing process, such as pressure and heating, can be adopted in the hardening process. Compared with ordinary concrete, RPC has the advantages of high strength, high toughness, high durability and good volume stability, but quartz sand, silica fume and steel fiber in RPC are all expensive materials. The price of steel fiber accounts for about 50% of the total cost of RPC, and no cheaper fiber material has been found to replace steel fiber in the current technical field. Therefore, in the process of RPC mix proportion design, optimizing the mix proportion design and minimizing the amount of steel fiber is an effective way to reduce the cost of RPC, which is of great significance to the promotion and application of RPC. In this paper, the influencing factors of mechanical properties of RPC are studied, including water-binder ratio, silica fume content, silica fume quality, silica fume state, fly ash and mineral powder content, steel fiber content, quartz sand gradation, etc., when the cementitious material is cement and mineral powder, When the minimum volume content of steel fiber is 1.2%, the quartz sand gradation is coarse, medium and fine, and the admixture is 2% of the cementitious material, the RPC, with mechanical properties satisfying the requirements is successfully prepared with silica fume, the lowest volume content of steel fiber is 1.2%, the quartz sand gradation is coarse, medium and fine, and the admixture is 2% of the cementitious material. The compressive strength and bending strength of RPC can reach 142.3 MPA and 19.0 MPA respectively. The elastic modulus can reach 49.0 GPA. The ability of RPC to resist chloride ion penetration and freeze-thaw damage was also studied by electroflux method and rapid freeze-thaw method. The experimental results show that when the content of mineral powder instead of cement is 15% and the volume content of steel fiber is 1.2%, the electric quantity of the RPC specimen is 25.7C at 6 h, and the mass loss of RPC is 4.0% after 600 freeze-thaw cycles. The relative dynamic elastic modulus is 74.6%, which is lower than the requirement that the mass loss rate of the specimen is 5% or the relative dynamic elastic modulus is reduced to less than 60%. It is shown that the RPC prepared by this ratio has excellent impermeability and frost resistance. It is determined that the final mixture ratio is cement: mineral powder: silica fume: quartz sand: steel fiber = 1 鈮，

本文編號：2490627