The present study investigates the properties of RPC (Reactive Powder Concrete) developed using low-cost eco-friendly materials such as pyrogenic silica (PS) and coir pith (CP) fine aggregates. This study investigates the effects of PS as silica fume (SF) replacement which is the main constituent for the production of reactive powder concrete which contained coir pith as a fine aggregate replacement instead of quartz sand (QS) up to 25%. The use of silica fume increases the particle packing density of RPC but increases the shrinkage phenomenon in RPC due to the minimum w/b ratio adopted. Therefore, in this research PS is used as a partial substitute for SF up to 30% and its effect on the mechanical and durability properties of coir pith containing RPC is studied. The test results showed that the mechanical strength values decreased with an increase in the addition of CP aggregate beyond 5% whereas the decrement in compressive strength was partially reduced when PS is used as silica fume replacement up to a maximum of 30%. The chloride penetration resistance was also improved with increasing PS substitution in RPC containing CP aggregates. The autogenous shrinkage and drying shrinkage were also significantly reduced due to the internal curing ability of the CP aggregates in combination with PS. The development of dense CSH (Calcium Silicate Hydrate) gels from hydration is also evident from the low CaO/ SiO2 ratio obtained from the EDS (Energy-dispersive X-ray Spectroscopy) analysis. Hence the combination of PS with CP aggregates can reduce the shrinkage characteristics of RPC thereby providing eco-friendly sustainable concrete at low cost.

本研究调查了使用低成本环保材料如热解二氧化硅 (PS) 和椰壳髓 (CP) 细骨料开发的 RPC（反应性粉末混凝土）的性能。本研究调查了 PS 作为硅粉 (SF) 替代品的影响，这是生产反应性粉末混凝土的主要成分，其中含有椰壳髓作为细骨料替代品，而不是高达 25% 的石英砂 (QS)。硅粉的使用增加了 RPC 的颗粒堆积密度，但由于采用的最小 w/b 比增加了 RPC 中的收缩现象。因此，在这项研究中，PS 用作 SF 的部分替代品，最高可达 30%，并研究了其对含有 RPC 的椰壳髓的机械和耐久性性能的影响。测试结果表明，随着 CP 骨料添加量的增加超过 5%，机械强度值下降，而当 PS 用作硅粉替代物时，抗压强度的下降部分减少，最高可达 30%。随着含有 CP 聚集体的 RPC 中 PS 取代度的增加，耐氯化物渗透性也得到改善。由于CP骨料与PS结合的内部固化能力，自收缩和干燥收缩也显着降低。从 EDS（能量色散 X 射线光谱）分析中获得的低 CaO/SiO2 比率也可以明显看出，从水合作用中形成致密的 CSH（水合硅酸钙）凝胶。