於德美　吴志鸿　郭晓　张峰　邱仁辉

摘要：为推广凝灰岩在道路工程中的应用，采用凝灰岩机制砂替代细集料，设计混合料级配，通过击实实验确定水泥稳定碎石最佳含水量和最大干密度，并制备试件，测试混合料无侧限抗压强度、劈裂强度、水稳性及抗冻性等路用性能。结果表明：3%和5%水泥用量的水泥稳定凝灰岩机制砂级配碎石可分别满足底基层和基层的强度要求;在较短龄期内，水泥稳定凝灰岩机制砂级配碎石无侧限抗压强度比水泥稳定天然集料的略高，劈裂强度相差不大，水稳系数接近;水泥用量对无侧限抗压强度影响显著。由此说明水泥稳定凝灰岩机制砂级配碎石总体性能满足道路基层使用要求。

关键词：水泥稳定基层;凝灰岩机制砂;无侧限抗压强度;劈裂强度;耐久性能

中图分类号：U414 文献标识码：A文章编号：1006-8023（2019）02-0099-08

Mixture of Graded Crushed Stone and Tuff Sands by Mechanical Extraction and its Application in Road Base Engineering

YU Demei 1， WU Zhihong 2， GUO Xiao 2， ZHANG Feng 2， QIU Renhui 1*

（1. College of Transportation and Civil Engineering， Fujian Agriculture and Forestry University， Fuzhou 350108; 2. Strait Construction and Development Co.， Ltd.， Fuzhou 350000）

Abstract：In order to promote the application of tuff mines in road engineering， the performance of cement-stabilized mixture of tuff sands by mechanical extraction and graded macadam was investigated. The unconfined compressive strength （UCS）， cleavage strength， water stability and frost resistance of the mixture were tested and compared with those of fine aggregates. The optimum water content and maximum dry density of cement-stabilized macadam with tuff sands were determined by compaction experiments. Results showed that the 3% and 5 % cement stabilized tuff sands mixed with graded macadam could meet the strength requirements of the sub-base and the base course， respectively. The UCS of tuff sands mixture was slightly higher than that of the cement-stabilized natural aggregate in a short period. The cleavage strength had insignificant difference between those of tuff sands mixture and fine aggregates mixture， while the cement usage had significant effects on it. The coefficient of water stability of cement-stabilized tuff sands mixture was very close to that of the cement-stabilized natural aggregates. Therefore， the tuff sands mixture was feasible for application in road base engineering basically.

Keywords：Cement stabilized base; tuff sands by mechanical extraction; unconfined compressive strength; cleavage strength; durability

0引言

凝灰岩是一种分布广泛的细粒火山碎屑岩，在东南沿海地区储量丰富。凝灰岩机制砂在混凝土中的应用已有研究 [1-2]，Messaouda等 [3]研究通过选用钙质凝灰巖代替天然河砂来进行混凝土试验，验证了钙质凝灰岩配制混凝土的可能性。Liguori等 [4]论证了采用凝灰岩配置环境友好型胶凝材料的可行性。李响等 [5- 6]对凝灰岩混凝土强度形成机理进行研究，结果发现凝灰岩对复合胶凝材料抗压强度的贡献更多体现在水化初期。温小栋等 [7]对凝灰岩机制砂混凝土抗硫酸盐侵蚀性能及机理进行了研究，但目前鲜有凝灰岩机制砂在道路工程应用方面的研究。……