硅烷偶联剂对集料表面改性的制备及性能表征

利用硅烷偶联剂对集料进行表面改性,使其与集料发生水解和固化反应。基于表面能理论、红外光谱(FTIR)和扫描电镜(SEM)等微观分析手段对改性前后的集料进行表征,通过直接拉伸、水煮法、浸水马歇尔试验和冻融劈裂试验等宏观手段对改性前后的集料性能进行验证。结果表明硅烷偶联剂表面改性后的集料接触角减小,由原来的亲水性变为亲油性;红外光谱(FTIR)发现硅烷偶联剂与集料之间产生了Si—O—C、Si—O—Si共价键和氢键;扫描电镜(SEM)观测到集料表面形成了一层聚硅氧烷偶联层薄膜,表明集料表面已引入了硅烷偶联剂中的亲油基团;浸水前后表面改性的集料比原集料抗拉强度损失率下降了42.2%;集料与沥青之间的粘附性等级可达到5级,沥青混合料残留稳定度提升11.54%,冻融劈裂强度比提升39.26%。说明了硅烷偶联剂成功对集料进行表面改性,并改善了集料的表面性能。

Preparation and characterization of surfacemodification of aggregate by silane coupling agent

The granules were surface modified with silane coupling agent to cause hydrolysis and solidification reaction with the aggregate.Based on surface energy theory,infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM),the aggregates before and after modification were characterized by direct stretching,boiling,water immersion Marshall test and freeze-thaw splitting test.The method was used to verify the aggregate performance before and after modification.The results show that the contact angle of the aggregate after the surface modification of the silane coupling agent was reduced,which changed from the original hydrophilicity to the lipophilicity.Infrared spectroscopy(FT-IR)shows that Si-O-C,Si-O-Si covalent bond and hydrogen bond were produced between the silane coupling agent and the aggregate.Scanning electron microscopy(SEM)observed that a polysiloxane coupling layer film was formed on the aggregate surface,indicating that the surface of the aggregate had been introduced into the silane coupling agent.The surface modified aggregate before and after water immersion reduced the tensile strength loss rate by 42.2%compared with the original aggregate.The adhesion grade between the aggregate and the asphalt could reach 5.The asphalt mixture residual stability increased by 11.54%and the freeze-thaw splitting strength ratio increased by 39.26%.These illustrate the successful surface modification of the aggregate by the silane coupling agent,by which the surface properties of the aggregate improved.