TiO_(2)改性钢渣基透水混凝土的力学和NO_(x)降解性能研究

Mechanical and NO_(x) Degradation Performance of TiO_(2) Modified Steel Slag-Based Permeable Concrete

以内掺纳米TiO_(2)为光催化剂,钢渣和矿渣粉为胶材,大钢渣颗粒为骨料,制备了TiO_(2)改性钢渣基透水混凝土(TSSPC),并研究了TiO_(2)掺量对TSSPC的抗压强度、透水性能和NO_(x)降解性能的影响。此外,结合XRD和SEM-EDX等微观测试分析方法,阐明了TiO_(2)对TSSPC力学性能、透水性能和光催化性能的影响机理,为TiO_(2)在透水混凝土中的应用奠定了基础。结果表明,当TiO_(2)掺量较少时,TiO_(2)颗粒的“晶核效应”对胶凝材料的早期水化有促进作用。但当TiO_(2)掺量较多时,TiO_(2)颗粒易发生团聚,不利于TSSPC的力学性能发展。此外,随着TiO_(2)掺量的提高,透水混凝土的连通孔隙率和透水系数均上升。相较于空白对照组,TiO_(2)掺量为5%(质量分数,下同)的TSSPC的连通孔隙率和透水系数分别提高了4.5个百分点和1.34 mm·s^(-1)。TSSPC对NO_(x)的降解效率随着TiO_(2)掺量(0%~5%)的增加而提高,当TiO_(2)掺量超过3%时,继续增加TiO_(2)掺量对NO_(x)降解效率的提升效果显著下降。

TiO_(2) modified steel slag-based permeable concrete(TSSPC)was prepared with nano-TiO_(2) incorporated as photocatalyst,steel slag and slag powder as binder,and large steel slag particle as aggregate.The effects of TiO_(2) content on the compressive strength,water permeability and NO_(x) degradation performance of TSSPC were studied.In addition,combined with microscopic test and analysis methods such as XRD and SEM-EDX,the effect mechanism of TiO_(2) on the mechanical properties,water permeability and photocatalytic performance of TSSPC was investigated,laying the foundation for the application of TiO_(2) in permeable concrete.The results show that when the TiO_(2) content is low,the“nucleation effect”of TiO_(2) particles promotes the early hydration of binder materials.However,when TiO_(2) content is high,TiO_(2) particles tend to agglomerate,which is harmful to the mechanical properties of TSSPC.In addition,as the TiO_(2) content increases,the connected porosity and water permeability coefficient of permeable concrete increase.Compared with the blank control group,the connected porosity and water permeability coefficient of TSSPC with a TiO_(2) content of 5%(mass fraction,the same below)increase by 4.5 percentage points and 1.34 mm·s^(-1),respectively.The NO_(x) degradation efficiency of TSSPC increases as the TiO_(2) content(0%~5%)increases.However,due to the agglomeration phenomenon,when the TiO_(2) content exceeds 3%,the effect of increasing the TiO_(2) content on NO_(x) degradation efficiency decreases significantly.