Improvement of unbound granular pavement layers and subgrade with cement dust in Egypt

Abstract

The main goal of this study is to assess the technical viability of using cement dust as part of the fines percentage in the unbound granular base/subbase pavement layers’ and subgrade soil as a viable sustainable solution. This study investigates the effect of adding cement dust to five types of pavement road materials which are collected from different ongoing roadway construction projects (1) Reclaimed Asphalt Pavement (RAP), (2) crushed stone base aggregates, (3) blend of crushed stone base aggregates with RAP, (4) crushed stone subbase aggregates, and (5) sandy subgrade soil. The resilient modulus (Mr) is selected as the main characteristic for evaluating the investigated materials’ stiffness. The regression parameters (k1, k2, and k3) of the universal Mr prediction model are found by fitting the experimental results of Mr testing for two replicates per each material type. The results show that using 3–5% of cement dust improves the estimated Mr of the investigated base/subbase materials and subgrades at the anticipated field stresses by 8–21%., As a result the structural layer coefficients are enhanced by 11–17%. KENLAYER nonlinear damage analysis confirms that using 3–5% of cement dust improves the predicted rutting life by up to 12% and the fatigue life up to 27%. Based on a typical pavement structure, enhancing pavement base/subbase layers and subgrade soils with 3–5% of cement dust reduces asphalt layer thickness from 11.25 to 12.50% and increases base/subbase layer thickness from 8.75 to 12.50% to maintain the same predicted rutting and fatigue lives of the typical structure. This positively affects the total construction cost in addition to the ecological benefits.

A Simplified Mechanistic-Empirical Flexible Pavement Design Method for Moderate to Hot Climate Regions

“…Many countries in Europe, Asia, and Africa have made efforts to prepare local design data, conducted sensitivity analyses, carried out the local calibration efforts, enhanced the pavement materials characteristics and modelling, and developed local calibration coefficients [24,[28][29][30][31][32][33][34][35][36][37][38][39][40]. Most of these countries used some default design inputs (traffic characteristics and material properties) instead of local data, due to the scarcity of the required data.…”

Laboratory Evaluation of Rice Husk and Sawdust on the Performance of Asphalt Binders and Mixtures. (Dept. C)

“…HERE is an increasing interest in the utilization of recycled and byproduct materials as alternative eco-materials in the civil engineering applications, especially in the pavement construction sector. Example of these eco-materials are reclaimed asphalt pavement, recycled concrete aggregate, demolition waste, marble dust, cement dust, crumb rubber, plastic waste, steel slag, waste oils, and others [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. There are many benefits of using such materials in which they minimize the utilization of raw materials, reserve landfills, and sustainability.…”