Additive for improving crack resistance of concrete and preparation method thereof

The invention provides an additive for improving the crack resistance of concrete and a preparation method thereof.The additive is prepared from, by weight, 1-2 parts of modified fiber, 7-9 parts of expanding agent and 5-7 parts of hydration heat inhibitor. The expanding agent is prepared from magnesite, dolomite, iron slag powder, natural gypsum and bauxite, and the cracking resistance of the concrete is further improved by controlling the calcination temperature and calcination time of the expanding agent. 本发明提出了一种提高混凝土抗裂性能的添加剂及其制备方法，按重量份计，包括以下原料，1-2份改性纤维、7-9份膨胀剂和5-7水化热抑制剂，本发明中通过对纤维素纤维改性制得改性纤维，使用菱镁石、白云石、铁渣粉、天然石膏、铝矾土制得膨胀剂，通过控制膨胀剂的煅烧温度、煅烧时间进一步提高混凝土的抗开裂性能。