This report presents information on the characterization of cementitiously stabilized layers and the properties that influence pavement performance. It also contains recommended performance-related procedures for characterizing these layers and performance-prediction models for incorporation into the mechanistic–empirical pavement analysis methods. Individual chapters highlight pavement distresses of hot-mix asphalt pavements and concrete pavements, laboratory tests and model development, and model calibration. The material contained in the report will be of immediate interest to state materials, pavement, and construction engineers and others involved in the different aspects of pavement design and construction.

Characterization of Cementitiously Stabilized Layers for Use in Pavement Design and Analysis

Shrinkage cracking occurs in cement-treated bases because of desiccation and cement hydration; eventually these cracks start to reflect through the pavement surfacing. Although initially considered cosmetic, these cracks open the pavement to water infiltration and increase the likelihood of accelerated pavement distress. Numerous options exist for minimizing the amount of reflective cracks that appear; microcracking is a promising approach. The microcracking concept can be defined as the application of several vibratory roller passes to the cement-treated base at a short curing stage, typically after 1 to 3 days, to create a fine network of cracks. In addition to the microcracked test sites, the contractor constructed moist-cured, dry-cured, and asphalt membrane–cured sites for comparison. Researchers used falling weight deflectometer (FWD) tests to control the microcracking process, periodic crack surveys to monitor crack performance, and FWD tests through time to track base moduli. Microcracking proved quite effective at reducing shrinkage cracking problems in the base; applying the procedure with three passes of the roller after 2 to 3 days of curing resulted in the best performance. In addition, researchers observed that, without microcracking, excessively high cement contents resulted in problematic cracking in the base even if they were cured according to good construction practice. Microcracking did not result in pavement damage or diminished in-service modulus; thus, microcracking should be considered a viable and inexpensive option to incorporate shrinkage crack control into the construction of cement-treated bases.

Use of Microcracking to Reduce Shrinkage Cracking in Cement-Treated Bases

This paper aims to develop measures to minimize the early-age fatigue damage of prematurely opened cement-treated bases (CTBs) due to repetitive heavy traffic loading. The four-point bendin...

Early-age fatigue damage assessment of cement-treated bases under repetitive heavy traffic loading

Cement stabilization is the most frequently used technique to enhance the mechanical properties of recycled materials. Reclaimed Asphalt Pavement (RAP) and Recycled Concrete Aggregate (RCA) are abundantly available recycled materials and utilization of these materials in road construction is a sustainable and eco-friendly process. However, the advantage of cement stabilization of RCA over RAP and blending with Conventional aggregates (VA) as a base and subbase course material at different stabilization levels is unknown. In the current study the same is investigated by stabilizing mixes with cement contents varying from 2 to 6% and blending with VA compared in terms of physical properties, compaction characteristics, and the performance tests like Unconfined Compressive Strength (UCS), Indirect Tensile Strength (ITS), and Modulus of Elasticity (E) at 7 days of curing period. From the results, it is observed that recycled aggregate blends need higher cement contents to satisfy the specifications as base layer for high volume roads and the stabilization of RCA is more pronounced compared with RAP. Significant improvement in strength is observed when blended with VA at all cement contents. However, RCA mixes achieved maximum strength at equal proportions of RCA and VA. No particular trend is observed in Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) for RCA blends due to the non-homogeneous distribution of mortar. The Elastic modulus of the RCA mixes declines with RCA content at higher cement content due to brittle nature. Summarily, 25% RAP, 25% RCA and 50% RCA blends at 6% cement performed well.

Evaluation of cement treated reclaimed asphalt pavement and recycled concrete pavement bases

Evaluation of flexural behaviour of cemented pavement material beams using distributed fibre optic sensors

To avoid early-age damage to cement-treated base (CTB) materials, the cement must be allowed to cure before the pavement can be opened to traffic. The purpose of this research was to evaluate the utilities of the soil stiffness gauge (SSG), the heavy Clegg impact soil tester (CIST), the dynamic cone penetrometer, and the falling weight deflectometer for assessing early-age strength gain of cement-stabilized materials. Experiments were performed at four sites on a pavement reconstruction project along I-84 in Morgan, Utah, where cement stabilization was used in conjunction with full-depth recycling. Each site was stationed to facilitate repeated measurements at the same locations with different devices and at different curing times. Because of the considerable attention from the pavement construction industry for routine quality control and quality assurance programs, the SSG and CIST were the primary focus of the research. Statistical techniques were used to evaluate the repeatability of these devices and...

Early-Age Strength Assessment of Cement-Treated Base Material:

EARLY-AGE STRENGTH ASSESSMENT OF CEMENT-TREATED BASE MATERIAL

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Tyler B. Young

Papers

Early-Age Strength Assessment of Cement-Treated Base Material:

Early Age Assessment of Cement Treated Materials