Cement Concrete Pavement Slab Research Articles

Treating by Self-Compensation Mud-Jack Materials for Voids Beneath Cement Concrete Pavement Slabs

In order to solve the problem that the domestic and overseas research on the mud-jack materials were used for treating voids caused voids again, based on Yantai-Weihai highway testing section as backing project, the cement, organic and sand mud-jack materials were improved by using the shrinkage-compensating principle. The rechecking results of core drilling indicated that the treating effect of recommended self-compensation mud-jack materials were good.

Numerical Simulation of the Process of Partial Void Formation under Cement Concrete Pavement Slab

The damage of void under cement concrete slab is one of the main diseases in cement concrete pavement. By finite element method, a 3-D model of cement concrete pavement structure was established to simulate the partial void under the cement concrete pavement slab with different loading conditions. The process of the division between the subgrade and the slab with a soft area under the slab are reappeared. The changing rules of the void size with the number of cycle load in case of different tie pressure and loading location (at the center, edge or corner of the slab).

Load Stress Analysis of the Impact of Parameters Variation on Super-Thick Cement Concrete Pavement

With the goal of exploring the impact of pavement structure parameters on load stress of super-thick cement concrete pavement, this paper, based on the Quanxing freeway in Guangxi, analyzes the load stress in the situation of the separated type and combined type contact between the cement concrete slab and the lean concrete base by using three-dimensional finite element model. Computational results show that the variation of different pavement structure parameters have various impacts on the load stress of super-thick cement concrete pavement. The load stress σc1 of super-thick cement concrete pavement slab declines with the increase of slab thickness h1 and base thickness h2 and decreases with the reduction of slab length L and the increases of base modulus E2 and subbase modulus Et. Among them, the variation of slab thickness h1 has the greatest impact on the pavement load stress. Thus, there is a quite obvious effect in reducing the pavement load stress by increasing the slab thickness.

Finite element study of partial-depth cracks in restrained PCC slabs

An existing finite element program—ISLAB2000—was modified to allow for the analysis of horizontally restrained and unrestrained portland cement concrete (PCC) pavement slabs with partial depth cracks. To simulate a partial-depth crack, special line spring elements were added to the ISLAB2000 finite element code. Previously published relationships between spring elements stiffness and crack depth were used for formulating the element stiffness matrix of the line spring elements and to calculate stress intensity factors after solving the system of finite element equations. Several example problems of partially cracked PCC slabs subject to typical highway loadings were solved to verify this newly developed finite element model termed ISLAB2005. The impact of crack depth and base friction parameters on slabs stresses and deflections was investigated. On the basis of this analysis, ISLAB2005 was found to be a reliable tool for analysis of partially cracked pavements that are either restrained or unrestrained from horizontal movements.

Finite Element Analysis of Concrete Pavements Over Culverts

Accelerated distress of Portland cement concrete pavements (PCCP) over structures such as culverts, pipes, and tunnels beneath roadways is a common occurrence. In this article, finite element analysis is employed to analyze the response of concrete pavements over such structures. The factors that influence the overlying pavement slabs include: (1) cover depth, (2) pavement slab thickness and length, (3) cement concrete elastic modulus, (4) foundation modulus, and (5) backfill soil modulus. The tensile stresses at the bottom and top of the slab induced by wheel loads are predicted. In the traditional pavement design only the tensile stress at the bottom of the slab is considered to be significant. However, this study shows that the tensile stress at the top surface of pavement slabs over culverts may also cause the concrete pavements to fail. A laboratory model was employed to study the mechanical characteristics of Portland cement concrete pavement slabs over culverts and to verify the theoretical analysis.

Finite Element Analysis of Pile-Supported Pavement Structures

A three-dimensional finite element analysis of pile-reinforced pavement systems was conducted. The parameteric study included both rigid and flexible airfield pavement systems. The influence of pile reinforcement in the subgrade was studied by comparing the surface deflections and the subgrade stresses in pile-reinforced pavement systems with those in nonreinforced systems. Changes in tensile stresses in concrete pavement slabs due to variations in pile stiffnesses were also examined. A reduction of surface deflection and subgrade stresses was observed in the pile-reinforced systems. The amount of reduction depended on the stiffness of the pile material. However, this reduction was accompanied by an increase in stress below the pile tips. A significant reduction of tensile stress in Portland cement concrete pavement slabs was noticed with increasing pile stiffness.