基于性能需求的机制骨料混凝土配合比设计

Mix Design of Manufactured Aggregate Concrete According to Performance Requirements

基于Dinger-Funk级配理论提出了机制骨料级配设计方法,通过修正Bolomey公式明确了适用于机制骨料混凝土的强度-水胶比关系;通过引入裹浆厚度概念建立了骨料与浆体之间的体积关系,并将机制砂中的石粉视作浆体组成,建立了机制骨料混凝土的配合比设计方法并进行了验证.结果表明:混凝土的工作性可以通过裹浆厚度来加以调控;混凝土的抗压强度和氯离子扩散系数与裹浆厚度无明显相关性,可以通过水胶比来加以调控;本文提出的配合比设计方法可以定量设计满足不同性能需求的机制骨料混凝土.

The mix design of manufactured aggregate was proposed based on the Dinger-Funk grading model.The mass relationship between binder and water for concrete with manufactured aggregate was determined by modifying the Bolomey’s formula.The paste thickness was introduced to establish the volume relationship between aggregate and paste.In addition,the stone powder in manufactured sand was considered as a component of the paste.Finally,the mix design method of concrete with manufactured sand was proposed and verified with concrete of different strength grades.The results show that the workability of concrete can be regulated by the paste thickness.The compressive strength of concrete and the diffusion coefficient of chloride have no obvious correlation with the paste thickness,with the water to binder ratio being the main factor regulating the hardened performance of concrete.The proposed mix design method can be used to quantitatively design concrete with manufactured aggregate for various performance requirements.