混凝土早期自收缩、强度与水泥水化率的关系

采用非接触式微位移传感器法对不同水灰比的混凝土从6h到28d龄期内的自收缩进行了测量,同时研究了密封条件下混凝土抗压强度与水泥水化发展过程。结果表明,随着水灰比的降低,混凝土自收缩和早期自收缩速率明显增大;对于同一混凝土而言,混凝土的抗压强度和水泥水化率均与自收缩成较好的线性关系;水灰比越低,同一龄期水泥的水化程度越低,水泥的化学收缩就越小,但混凝土的自收缩值却越大,证明自收缩与化学收缩是两个不同的物理量。

THE RELATIONSHIP AMONG CEMENT HYDRATION DEGREE, COMPRESSIVE STRENGTH AND AUTOGENOUS SHRINKAGE OF CONCRETE AT EARLY AGES

Autogenous shrinkage of concrete with different water-cement ratios was measured from 6 hours to 28 days with a new method. This measurement method adopts a type of micre-displacement sensor and the concrete is not to be touched during the test. Development of concrete compressive strength and cement hydration process were also studied under the sealed curing condition. The results show that autogenous shrinkage and early age aotogenous shrinkage speed of concrete increase remarkably with the decreasing of water-cement ratio. For every concrete, the relation between autogenous shrinkage and compressive strength or cement hydration degree at early ages ean be well figured by a linear equation. The lower the water-cement ratio is, the higher the autogenous shrinkage of conerete, but the lower the cement hydration ratio and chemical shrinkage of concrete is at the same ages. Therefore it is demonstrated that autogenons shrinkage and chemical shrinkage are two different physical quantities.