Search

This paper presents an application of the continuous intrusion miniature cone penetration testing for the evaluation of the resilient modulus of cohesive soils. Four cohesive soils were selected for the field and laboratory testing program. The field tests were performed on these soils using the continuous intrusion miniature cone penetration test system. The laboratory testing program included repeated load triaxial tests on undisturbed soil samples, and soil physical and strength properties testing. A statistical analysis was performed on the test results of two soils in order to develop a correlation among the resilient modulus, cone penetration test parameters, in-situ stresses, and soil properties. The model was used to predict the resilient modulus of other two soils. The predicted and measures values of the resilient modulus were in agreement.

This paper investigates the applicability of the cone penetration test in determining the resilient modulus of coarse-grained materials. Field and laboratory investigations were conducted at the sites of two pavement projects in Louisiana. Field tests consisted of continuous intrusion miniature cone penetration tests and soil sampling. Laboratory tests included the repeated load triaxial test and other tests for materials characterization. The test results were used to develop a correlation for predicting the resilient modulus of coarse-grained materials using the cone penetration test parameters and basic soil properties. Another laboratory investigation was conducted in order to investigate the effect of moisture content and unit weight on the cone penetration test parameters and resilient modulus. Test results were used to validate the model developed for predicting the resilient modulus. The resilient modulus values predicted were consistent with those obtained using the repeated load triaxial test.

Bottom ash, a byproduct of the coal combustion process to generate electricity by power plants, is generally underutilized and ends up in landfills or ponds. This paper aims at evaluating the characteristics of the coal combustion bottom ash for potential utilization in pavement construction materials. To achieve this objective, a comprehensive laboratory testing program was undertaken to evaluate the physical properties, compaction characteristics, and resilient modulus of bottom ash, subgrade soils, and bottom ash-soil mixtures. The investigated bottom ash was obtained from power plants in Wisconsin and Michigan. Test results showed that there is a wide spectrum of bottom ash properties pertaining to specific gravity and unit weight, while the investigated bottom ash samples were classified as granular material. Repeated load triaxial testing was performed to determine the resilient modulus of the bottom ash, subgrade soil, and bottom ash-soil mixtures. Specimens were tested at the maximum dry unit weight and optimum moisture content. Test results demonstrated that the resilient modulus values of bottom ash vary depending on the physical properties and unit weight of the bottom ash. For four bottom ash-soil mixtures, the resilient modulus values were low compared with the resilient modulus of subgrade soils, while for one type the resilient modulus was comparable/higher than that of subgrade soil. Therefore, mixing the bottom ash with subgrade soil showed increased resilient modulus values of the mixture for the bottom ash sample from Oak Creek Power Plan (OCPP). Mixing 50% of the bottom ash with subgrade soil, by dry weight, was considered an optimum amount to improve the resilient modulus of the bottom ash soil mixture for OCPP bottom ash.

This paper presents a probabilistic CPT method to estimate the ultimate capacity of driven friction piles utilizing CPT data. A database of 35 square PPC piles that were loaded to failure and their adjacent CPT were used to develop this method. Backcalculation was carried out to calibrate the correlation factors needed to determine the unit end bearing (qb) and unit skin friction (f) of the pile from CPT data (qc, fs) based on the probability of having each soil type. The ultimate pile capacities (QP) of the investigated piles estimated by the proposed method, three other CPT methods, and static α and β methods were compared with the measured pile capacities obtained from pile load tests. Statistical analyses were carried out to evaluate the reliability of the probabilistic CPT method and the results showed that the proposed method can predict the ultimate capacity of the piles with good accuracy. The capability of the proposed method was further verified by predicting the capacities of an additional 17 pile load tests. The probabilistic CPT method, in addition to Schmertmann, α, and β methods were calibrated to evaluate the resistance factors needed for the design of single driven piles based on the LRFD method.