橡胶颗粒-钢纤维混掺对碾压混凝土抗冻性及抗冲击性能的影响

本文研究了在质量分数为25%的醋酸钾（KAc）为冻融介质的环境中，橡胶颗粒（RP）-钢纤维（SF）混掺对碾压混凝土（RCC）抗冻性及抗冲击性能的影响，获得了冻融过程中RCC的抗弯冲击性能、相对动弹性模量、质量损失、微观形貌及孔结构变化等参数。结果表明：RCC累计质量损失随冻融次数增加而增大，RP对质量损失的影响较小，而SF能较明显控制质量损失快速增长，300次冻融循环后累计质量损失仅83.94 g/m²； RP能降低RCC的总孔隙率约0.6%，而SF能有效降低总孔隙率，但冻融后期锈蚀作用会导致总孔隙率迅速增长； SF能极大RCC提高抗弯冲击性能，试验条件下抗冲击次数从3~5次水平提升至140~170次水平，而RP对冲击性能并无明显影响，冻融结束掺有SF试验组RCC初、终裂次数降幅超过70%，但终裂次数仍达到30~40次的水平，绝对韧性均随冻融次数增加逐渐降低； RCC相对动弹模量均表现出先降低后缓慢回升的规律，掺有SF试验组下降阶段相对更短且幅度更小，最大仅8%，而RP影响并不明显，但4组降低程度均在10%内。

Frost resistance and impact properties of roller compacted concrete mixed with rubber particles and steel fibers

In this paper, the frost resistance and impact resistance of roller compacted concrete (RCC) mixed with rubber particles(RP) and steel fiber(SF) were investigated in 25% (by mass) potassium acetate (KAc) as the medium in freezing-thawing cycles. The flexural impact performance, relative dynamic elastic modulus, mass loss, microstructure, and pore structure of RCC were measured. The results show that the accumulated mass loss of RCC increases with the increase of freeze-thaw cycles. The RP have slight effect on the mass loss, the total porosity, the impact property and relative dynamic elastic modulus of RCC. However, the SF can obviously control the rapid growth of the mass loss and improve the flexural impact property. The cumulative mass loss of RCC with 300 freeze-thaw cycles is only 83.94 g/m². The impact number of RCC with 1.3% (by volume) SF raises from 3-5 to 140-170. The initial and final impact number decreases by 70% after RCC specimens being subjected to 300 freeze-thaw cycles. The relative dynamic elastic modulus firstly decreases and then has a slow increase at the later stage. The maximum loss of relative dynamic elastic modulus is 8% when the SF reinforced RCC with 300 freeze-thaw cycles. The loss of relative dynamic elastic modulus of all specimens is less than 10%.