新成型水泥混凝土路面板内水分及气体竖向分布

Vertical distribution of water and air in new molding cement concrete pavement slab

为分析影响水泥混凝土路面板路用性能的深层次原因,寻找改善路用性能的方法,以硬化前路面板内水分与气体的竖向分布为切入点,通过改变道路混凝土中的用水量、水泥用量、砂浆体积分数及引气剂掺量,进行了模拟成型的水泥混凝土路面板的含水量、含气量竖向分布规律研究,并利用扫描电镜进行了微观形貌分析。研究结果表明:成型后水泥混凝土路面板表面砂浆层的含水量和含气量均高于面板内部;含水量的增加会导致结构内部孔隙率的提高及大孔数量的增加,这将降低混凝土的抗渗性能;而较高的含气量虽然使混凝土的孔隙率增大,但只增加了小孔数量,使孔径分布更加均匀,改善了微观孔结构,有利于水泥混凝土的耐久性。

To study the underlying causes which affect pavement performance ot cement concrete pave- ment slab and find the way to improve pavement performance, the vertical distribution of water and air in concrete pavement slab was taken as key point and the distribution of water and air in cement concrete pavement slab was researched by changing the amount of water, amount of cement, volume fraction of mortar and volume of air-entraining admixture. SEM was used to analyze the micro-structure of mortar layer of cement. The results show that： the contents of water and air inside the cement concrete pave- ment slab are less than that in the surface; pore fraction and the number of big pores of cement structure are increased by higher water content, which will reduce the impermeability of cementl higher air content increases pore fraction of cement structure too, but it just increase the number of small pores, which makes pore sizes distribution more uniform and improves the micro-structure. Thus the durability of ce- ment concrete is improved. 8 tabs, l1 figs, 12 refs.