气化炉渣的碱活性研究

Study on alkali reactivity of gasifier slag

目前混凝土骨料资源短缺问题突显,气化炉渣是潜在资源.若采用气化炉渣作细骨料,首先需要判别气化炉渣的碱活性.试验按照砂浆棒快速法研究气化炉渣的碱活性,用三个主要粒级的气化炉渣替代天然砂制作砂浆棒,测定各龄期砂浆棒的长度.试验结果表明天然砂砂浆棒28d的膨胀率为0.09%,而含有气化炉渣的各组砂浆棒膨胀率均小于0.06%,且0.63mm粒级是碱硅酸型碱骨料反应的敏感粒级.作为混凝土细骨料使用时,气化炉渣不属于碱活性骨料,反而对碱骨料反应膨胀有一定抑制作用.应用于混凝土时,不必担忧气化炉渣会引起碱骨料反应危害.

Nowadays,the shortage problem of aggregate resources for concrete is conspicuous,however,gasifier slag can be considered as a potential resource.Firstly,the alkali reactivity of gasifier slag must be determined if it is used as fine aggregate.The mortar bar experiment in rapid method was performed to study the alkali reactivity of gasifier slag.The experimental mortar bars were prepared by substituting gasifier slag for natural sand in three main size fractions,and length values of mortar bars at each age were measured.The results show that the expansion ratio of control sample at 28 days is 0.09%,while the expansion ratio of each group of mortar bar substituted gasifier slag for part of natural sand is less than 0.06%.The most sensitive size fraction for alkali-silica reaction in types of alkali-aggregate reactions is 0.63 mm.Therefore,gasifier slag is non-reactive aggregate when it is used as fine aggregate for concrete,contrarily,it has inhibitory effect on expansion caused by alkali-aggregate reaction.It is not necessary to worry about alkali-aggregate reaction risk induced by gasifier slag when it is applied in concrete.