再生微粉和矿物掺合料对混凝土抗碳化性能的影响研究

Influences of Recycled Fine Powder and Mineral Admixtures on Carbonization Resistance of Concrete

利用快速碳化试验研究了单掺再生微粉、单掺粉煤灰及复掺再生微粉(RFP)、粉煤灰(FA)及硅灰(SF)等三种掺配方式对混凝土抗碳化性能的影响规律,并借助SEM、XRD等方法分析了碳化作用对混凝土微观结构的影响。研究结果表明:单掺再生微粉或粉煤灰对混凝土的抗碳化性能具有显著影响,相同取代率下单掺再生微粉的抗碳化性能优于单掺粉煤灰的;复掺再生微粉、粉煤灰及硅灰后可以明显改善混凝土抗碳化性能,其中RFP∶(FA+SF)=7∶3时混凝土的抗碳化性能最优,当取代率为40%时,碳化深度最高为14.6 mm。碳化后生成的碳酸钙固体可以填充混凝土中的孔隙,提高混凝土内部的密实度。

The rapid carbonization experiment was used to study the influence of three mixing methods,such as single-recycled fine powder,single-fly ash and mixed-recycled fine powder,fly ash and silica fume,on the carbonization resistance of concrete.With the help of SEM,XRD and other methods,the effect of carbonization on the microstructure of concrete was analyzed.The results show that mixing with recycled fine powder or fly ash has a significant effect on the anti-carbonization performance of concrete.At the same substitution rate,the concrete with recycled fine powder only has better carbonization resistance than that of the concrete with fly ash only.Mixing with recycled fine powder,fly ash and silica fume obviously improves the carbonization resistance of concrete.Among them,when the ratio of RFP∶(FA+SF)is 7∶3,the concrete has the best carbonization resistance,when the substitution rate is 40%,the maximum carbonization depth is 14.6 mm.The calcium carbonate generated after carbonization fills the pores in the concrete and improve the internal density of the concrete.