REVIEW OF EXPANSIVE ALKALI-AGGREGATE REACTIONS IN CONCRETE. TECHNICAL NOTE
REVIEW OF EXPANSIVE ALKALI-AGGREGATE REACTIONS IN CONCRETE. TECHNICAL NOTE
复制标题
混凝土中广泛的碱骨料反应的回顾。
DOI：
10.1061/(asce)0899-1561(1995)7:4(278
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
J. Gillott
中科院分区：
文献类型：
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作者：
J. Gillott
碱-集料反应（AAR）是世界范围内常见的导致波特兰水泥混凝土耐久性失效的主要原因。有害AAR通常导致素混凝土的膨胀和地图开裂;然而，在钢筋或预应力混凝土中，裂缝可能与钢筋呈线性关系。膨胀会导致屈曲、接缝填充物的挤压以及混凝土中设备的位移。膨胀还可导致硅胶的白色沉积、聚集体颗粒周围的边缘、突出、强度损失和弹性模量降低。损坏可能非常严重，以至于必须更换混凝土，但当损坏不太严重时，已经尝试了不太激烈的补救措施。使用岩相学方法，长度变化试验，并检查类似恶化的混凝土，骨料可能会导致膨胀AAR可以确定。通过减少混凝土中碱的有效供应、矿物和化学外加剂的使用、限制润湿的设计以及骨料的软化，可以最大限度地减少AAR引起的潜在膨胀。本文综述了膨胀反应的类型和膨胀机理的分类。
Expansive alkali-aggregate reactions (AAR) occur frequently worldwide, causing durability failure in Portland cement concrete. Deleterious AAR generally result in expansion and map-cracking in plain concrete; however, in reinforced or prestressed concrete, cracks may display a linear relationship to reinforcement. Expansion can lead to buckling, extrusion of joint filler, and displacement of equipment set in concrete. Expansion can also cause white deposits of silica gel, rims surrounding aggregate particles, pop outs, loss of strength, and decrease in modulus of elasticity. Damage may be so extreme that concrete has to be replaced, but less drastic remedial measures have been tried when the damage is less severe. Using petrographic methods, length-change tests, and examination of similarly deteriorated concrete, aggregates likely to cause expansive AAR can be identified. Potential expansion due to AAR may be minimized by decreasing the available supply of alkalies in concrete, use of mineral and chemical admixtures, design to limit wetting, and the beneficiation of aggregates. The author reviews classification of the types of reaction and mechanisms of expansion.