掺橡胶粉防水轻质混凝土材料性能研究

Properties of Lightweight Concrete for Waterproofing Mixed with Rubber Powder

为了改善建筑物防水性能,通过研究橡胶粉掺量对轻质混凝土流动性、强度和防水性能的影响,借助CT图像分析探讨了橡胶粉掺量对轻质混凝土微观结构的影响。研究表明:橡胶粉提升了气泡间摩阻力,增大了浆体粘稠度,降低了轻质混凝土的流动性;适量的橡胶粉可降低轻质混凝土的导热系数,填补基体部分孔隙,改善防水性能。随掺量增大,橡胶粉吸附周围气泡,并大面积上浮,产生连通孔,破坏混凝土孔结构,抗压强度下降;采用CT图像分析发现,当橡胶粉掺量超过3%时,基体孔隙增大,形成界面层和弱界面过渡区,易出现应力集中产生断裂,其力学和防水性能下降。

In order to improve the waterproof performance of building,the influences of rubber powder content on the fluidity,strength and waterproof performance of lightweight concrete were investigated.With the aid of CT image analysis,the influence of rubber powder content on the microstructure of lightweight concrete is discussed.Studies have shown that:rubber powder increases the frictional resistance between bubbles,increases the viscosity of the slurry,and reduces the fluidity of lightweight concrete.Since the rubber powder itself is waterproof and has good thermal insulation performance,an appropriate amount of rubber powder can reduce the thermal conductivity of lightweight concrete,fill some pores in the matrix,and improve the waterproof performance of the pore wall.With the increase of the content,the rubber powder adsorbs the surrounding air bubbles and floats on a large area,resulting in connected pores,destroying the pore structure of the lightweight concrete,and reducing the compressive strength.CT image analysis found that when the amount of rubber powder exceeds 3%,the foams merge with each other,which makes the matrix pores increase,forming an interface layer and a weak interface transition zone,which is prone to stress concentration and breakage,and its mechanical and waterproof properties are reduced.