养护方式对白色高强混凝土氯离子渗透的影响

EFFECT OF CURING REGIMES ON CHLORIDION PENETRATION OF WHITE HIGH-STRENGTH CONCRETE

通过快速氯离子扩散系数法研究了不同养护方式对白色混凝土抗氯离子渗透性能的影响。结果表明:纯白水泥混凝土在三组养护方式中抗氯离子渗透性最差,使用矿物掺合料可大幅度降低白水泥混凝土的快速氯离子扩散系数(DRCM);标准养护下混凝土的DRCM最低,匹配养护较高,蒸汽养护最高;白水泥早期水化剧烈,第二放热峰出现时间最早,峰值最高,但累积放热量次于普通水泥;纯白水泥混凝土绝热温升最终温度最高,水泥-矿粉体系混凝土次之,水泥-矿粉-石灰石粉最低;经孔结构分析可知,蒸汽养护虽可激发混凝土水化进程,降低孔隙率,但会促使孔结构往粗孔方向发展,平均孔径增大。

The rapid chloridion diffusion coefficient method was used to study the effect of different curing regimes and the use of mineral admixture on chloridion resistance of white concrete.The results showed that the pure white cement concrete had the lowest resistance to chloridion penetration among the three groups of curing regimes.The use of mineral admixtures could greatly reduce the rapid chloridion diffusion coefficient(DRCM)of the white cement concrete;the DRCM of the concrete under standard curing was the lowest,the value of matching curing was the second high and that of steam curing was the highest;the second exothermic peak of white cement hydration in the early stage appeared earliest,and its peak was the highest data.However,the cumulative heat release of pure white cement was lower than that of ordinary cement.In addition,the pure white cement concrete had the highest adiabatic temperature rise(ATR)and the highest temperature,the concrete with cement-mineral powder system possessed the second-high ATR and the concrete with cement-mineral powder-limestone powder had the lowest value.Through the pore structure analysis,it could be seen that although steam curing might stimulate the hydration process of the concrete and reduce the porosity,it would promote the pore structure to develop toward the rough pore and would increase the average pore diameter.