再生混凝土徐变试验及老砂浆影响机理研究

通过改变再生粗骨料取代率(0%、50%、100%),对再生混凝土的徐变性能进行试验研究,并在此基础上,针对再生混凝土徐变高、离散性大的特点,采用分相研究的方法对再生混凝土徐变过程中天然骨料、老砂浆和新砂浆的相互作用机制进行研究,从而揭示了再生混凝土的徐变机理,建立了反映老砂浆影响机理的再生混凝土徐变预测模型.结果表明:再生混凝土的徐变度随着再生粗骨料取代率的增加而增加;老砂浆的徐变及其含量对再生混凝土的徐变具有较大影响,降低再生混凝土中老砂浆的徐变和含量是实现再生混凝土低徐变的有效途径;模型预测值与试验值的对比表明,所建立的预测模型可以较好地预测再生混凝土的徐变.

Study on Creep Test of Recycled Coarse Aggregate Concrete and Influence Mechanism of Old Mortar

Test on creep of recycled coarse aggregate concrete(RAC) was conducted by varying the recycled coarse aggregate(RCA) replacement rate(0%, 50%, 100%). Base on test results, split phase research method was adopted to study the interaction mechanism among natural aggregate, old adhered mortar and new mortar in the creep process of RAC for the high values and large discreteness of creep of RAC. Thus creep mechanism of RAC was revealed and creep prediction model of RAC was established. The results show that specific creep of RAC increases with the increases of RCA replacement rate; the influence of creep and content of old mortar on creep of RAC is significant; reduction of the creep and content of old mortar are effective way to realizing low creep of RAC; and the comparison between test values and prediction values indicate that the prediction model can predict creep of RAC well.