Jirayut Suebsuk

Strength prediction of cement-stabilised reclaimed asphalt pavement and lateritic soil blends

Abstract In this research, marginal lateritic soil (LS) was used for improving the gradation properties of reclaimed asphalt pavement (RAP) prior to cement stabilisation for heavy and light-volume roads. The unconfined compressive strength (q u ) of cement-stabilised RAP–marginal LS blends was found to increase with LS replacement due to the improvement of gradation properties and lower asphalt binder content. The soil–water/cement ratio (w/C) was successfully implemented for a particular RAP:LS ratio to integrate the effects of water and cement contents on strength development at the optimum water content and on the wet side of optimum. By incorporating a new parameter termed as the asphalt binder content (AS), a general strength relation equation was proposed for various water contents, cement contents and RAP:LS ratios. The general strength relation of cement-stabilised RAP-marginal LS blends is presented based on three critical material constants, which are A*, B* and k . The A* and B* constants mainly depends on curing time, while the k constant is essentially the same. The general strength relation was furthermore validated with measured strength data. The general strength relation is useful as a mix design tool for determining the optimal input of cement for various RAP:LS ratios to meet strength requirement for base and subbase applications. A mix design method with a minimum trial test is furthermore proposed in this paper.

STRENGTH ASSESSMENT OF CEMENT TREATED SOIL- RECLAIMED ASPHALT PAVEMENT (RAP) MIXTURE

The article attempts to present the influence of reclaimed asphalt pavement (RAP) content on the compaction behavior and unconfined compressive strength of cement treated soil-RAP mixture. The laboratory compaction and unconfined compression tests on cement treated soil-RAP mixture were carried out with various RAP and cement contents. The porosity was adopted as a state parameter for assessing the strength of the mixed materials. The results show that with an increase in RAP content, the OMC tends to decrease, up to the optimum of soil/RAP ratio of 50/50. The asphalt fixation point is designated as a transitional point where less change in strength turns to a larger change. An asphalt content of 3.5% (50/50 soil/RAP ratio) is found to be the asphalt fixation point. The strengths, where the asphalt content is lower than the asphalt fixation point, can be predicted by the proposed generalized form of strength. This proposed equation can assess the laboratory strength of cement treated soil-RAP mixture under various mixed proportions, cement contents, water contents, and curing times.

Water Treatment Sludge–Calcium Carbide Residue Geopolymers as Nonbearing Masonry Units

AbstractIn this research, water treatment sludge (WTS) calcium carbide residue (CCR) geopolymers were evaluated as a sustainable masonry nonbearing unit. The WTS was a by-product from a water treat...

Finite element analysis of consolidation behavior of composite soft ground

Columnar inclusion is one of the effective and widely used methods for improving engineering properties of soft clay ground. This paper investigates the consolidation behavior of composite soft clay ground using both physical model tests under an axial-symmetry condition and finite element simulations using the PLAXIS 2D program. Because the soil-cement column enhances the yield stress and stiffness of the composite ground, the composite ground is in an over-consolidated state under the applied vertical applied stresses. At this state, the rate of consolidation is rapid due to a high coefficient of consolidation. The consolidation of the composite ground is mainly controlled by the area ratio, the ratio of the diameter of the soil-cement column to the diameter of the composite ground, a . As the area ratio increases, the rate of consolidation increases and the final settlement decreases.