沸石粉/相变材料改性混凝土力学性能及早期抗裂性

Mechanical Properties and Early Crack Resistance of Zeolite/Phase Change Material-Modified Cement-Based Materials

混凝土抗拉强度低、应变能力差,其开裂问题是现今世界工程建设的一大难题。以沸石粉(ZP)为矿物掺合料兼内养护材料、石蜡-硬脂酸丁酯(S-Y)为相变材料,研究了ZP和S-Y复掺对混凝土力学性能及早期抗裂性的影响及影响规律,并通过MIP、XRD和SEM等分析探讨了复掺改性的微观机理。结果表明,ZP和S-Y复掺改性混凝土力学性能及早期抗裂性的最佳掺量分别为10%和6%。与不含沸石粉的对照组试件相比,28 d的抗折和抗压强度分别提高了19%和22%,氯离子迁移率较低,仅为4.8×10^(-12)m^(2)/s,且混凝土板并未出现开裂现象。复掺改性机理源于沸石粉和相变材料协同作用促进了水化产物的增多,密实了硬化浆体的微结构,缓解了水化早期的温度应力。

Due to the low tensile strength and poor capacity for deformation,concrete are brittle and highly sensitive to cracking,which is still a major problem in engineering construction worldwide.In this regard,it was studied here that the influence of zeolite powder(ZP),as mineral admixture as well as internal curing agent,and butyl stearate paraffin(S-Y),as phase change material,on the mechanical properties and early crack resistance of concrete.The microscopic mechanism of modification was discussed through MIP,XRD and SEM test results.The results show that the optimum contents of ZP and S-Y are 10%and 6%,respectively.Compared with the control group without ZP,the flexural strength and compressive strength are increased by 19%and 22%,respectively.The chloride mobility is lower,only 4.8×10^(-12)m^(2)/s,and the concrete slab does not crack.The compound modification mechanism is attributed to the synergistic effect of zeolite powder and phase change material to promote the increase of hydration products,compact the micro-structure of hardened concrete,and alleviate the temperature stress at the early stage of hydration.