基于响应曲面法硅藻土改性沥青混合料性能研究

Response surface method for performance of diatomite modified asphalt mixture

为优化硅藻土改性沥青混合料配合比设计,基于曲面响应法,以油石比、硅藻土掺量和硅藻土细度3个因素为试验变量,以马歇尔稳定度、残留稳定度以及低温劈裂强度为响应指标,采用Box-Behnken模型进行沥青混合料试验设计,共17组试验方案;对试验结果进行回归分析,建立二次函数模型,分析3因素的最优配比。试验结果表明:当油石比为4.5%,且硅藻土的掺量和细度分别为20%和500目时,最终的响应指标马歇尔稳定度、残留稳定度及低温劈裂强度分别为15.55 kN、97%、4.13 kPa,所制备的沥青混合料能够符合甘肃陇东地区要求,且综合性能达到最优。硅藻土的掺入可有效提高沥青混合料的各项性能,其中以高温性能的提高最为显著;曲面响应法预测值与实际试验值之间最大误差未超过2.7%,表明曲面响应法模型能够较准确地预测三因素对沥青混合料性能影响的程度,将响应曲面法应用于硅藻土沥青混合料的设计及优化具有良好的适用性和优势。

In order to optimize the ratio design of diatomaceous earth modified asphalt mixture,on the basis of the surface response method,the Box-Behnken model was used to carry out the experimental design of asphalt mixture with three factors of oil to stone ratio,diatomaceous earth admixture and diatomaceous earth fineness as the experimental variables and Marshall stability,residual stability and low-temperature splitting strength as the response indicators,with a total of 17 test scenarios;regression analysis was performed on the test results to establish a quadratic.The regression analysis was performed to establish the quadratic function model,and the optimal ratio of the three factors was finally calculated.The test results show that when the oil to stone ratio is 4.5%,and the diatomaceous earth admixture and fineness are 20% and 500 mesh respectively,the final response index Marshall stability,residual stability and low temperature splitting strength are 15.55 kN,97% and 4.13 kPa respectively,the prepared asphalt mixture can meet the environmental requirements in Longdong area of Gansu and the comprehensive performance is optimal.The maximum error between the predicted and actual test values of the surface response method did not exceed 2.7%,indicating that the surface response method model can predict the influence of three factors on the performance of asphalt mixtures more accurately,and the response surface method can be applied to the design and optimization of asphalt mixtures with diatomaceous earth.The application of the response surface method to the design and optimization of diatomaceous earth asphalt mixtures has good applicability and advantages.