Application of Dynamic Cone Penetrometer in Pavement Construction Control

Author(s):  
Murad Y. Abu-Farsakh ◽  
Munir D. Nazzal ◽  
Khalid Alshibli ◽  
Ekram Seyman

A comprehensive testing program was conducted to evaluate the potential use of the dynamic cone penetrometer (DCP) in the quality control–quality assurance procedure during the construction of pavement layers and embankments. The laboratory tests were conducted on different materials prepared inside two test boxes measuring 1.5 m x 0.9 m x 0.9 m (5 ft x 3 ft x 3 ft) located at the Louisiana Transportation Research Center (LTRC). The field tests were performed on different highway sections in Louisiana. In addition, nine test sections were constructed and tested at the pavement research facility site of the LTRC. In all laboratory and field tests, DCP tests were carried out in conjunction with the plate load test (PLT). Also, falling weight deflectometer (FWD) tests were carried out on the field sections. California bearing ratio (CBR) laboratory tests were performed on samples collected from the tested sections. Regression analysis was carried out on the collected data to correlate the DCP penetration rate with the three reference tests used in this study (PLT, FWD, and CBR). Further field tests were conducted to verify the developed regression models. The results showed that the developed models yielded good predictions of the measured FWD moduli and CBR values. This suggests that these models can be used reliably to evaluate the stiffness and strength of pavement materials.

2020 ◽  
Vol 2 (1) ◽  
pp. 18-28
Author(s):  
Junhui Zhang ◽  
Le Ding ◽  
Ling Zeng ◽  
Qianfeng Gao ◽  
Fan Gu

Abstract Based on a highway reconstruction project in southern China, this study aims to put forward a method to determine the proper treatment depth of the existing subgrade. First, some field tests including the Beckman beam deflection test and portable falling weight deflectometer (PFWD) test were carried out. The results showed that there was a good correlation between the Beckman beam deflection (L) and PFWD modulus (Ep). Subsequently, a subgrade section was excavated and backfilled with cement-stabilized soil in layers. Compaction test, dynamic cone penetrometer rate test, plate load test and Beckman beam deflection test were performed to evaluate the treatment effect. To make sure, the subgrade was treated deeply enough, the Beckman beam deflection (L) was used as the controlled indicator among all the measured indexes for it was the hardest metric to meet. According to the design deflection and decreasing law of the measured deflections with the different number of the stabilized layers, the treatment depth was finally determined. As the PFWD test is superior to the deflection test in the detection efficiency, and the deflection value can be calculated from PFWD modulus by correlation formulas, thus the latter index can be used as a more suitable parameter for estimating the treatment depth instead of the former. Consequently, based on the measured PFWD moduli of the existing subgrade, six treatment schemes considering different treatment depths were proposed. It was confirmed that the method developed from this study is feasible and worth being extensively applied.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Fengyu Ren ◽  
Huan Liu ◽  
Rongxing He ◽  
Guanghui Li ◽  
Yang Liu

The point load test (PLT) is intended as an index test for rock strength classification or estimations of other strength parameters because it is economical and simple to conduct in the laboratory and in field tests. In the literature, calculation procedures for cylinder cores, blocks, or irregular lumps can be found, but no study has researched such procedures for half-cylinder cores. This paper presents the numerical model and laboratory tests for half-cylinder and cylinder specimens. The results for half-cylinder and cylinder specimens are then presented, analysed, and discussed. A correlation of failure load between half-cylinder and cylinder specimens is established with a suitable size suggestion and correction factor. It is found that the failure load becomes stable when half-cylinder specimens have a length/diameter ratio higher than 0.9. In addition, the results show that the point load strength index (PLSI) of half-cylinder cores can be calculated using the calculation procedures for diametral testing on cylinder cores, and it is necessary to satisfy the conditions that the length/diameter ratio be higher than 0.9 and the failure load be multiplied by 0.8.


Author(s):  
Dallas N. Little

Lime-stabilized clay subgrades are used almost routinely in Texas to facilitate construction and to provide a foundation for aggregate base courses and hot mix surfaces. Research sponsored by the Texas Department of Transportation demonstrates that the in situ moduli and strength improvements afforded by lime stabilization of these layers are often significant and deserve structural consideration. A study of the range of modulus values determined from falling weight deflec-tometer deflection data and supported by in situ dynamic cone penetrometer data for 40 pavement subgrades indicates that the lime-stabilized subgrades provide a level of stiffness and strength that is similar to that of an unbounded aggregate base. This substantiates previous literature suggesting that properly designed and constructed lime-stabilized subgrades should be assigned AASHTO structural coefficients in the same range as unbound aggregate bases, that is, between 0.10 and 0.14.


1998 ◽  
Vol 35 (5) ◽  
pp. 801-810 ◽  
Author(s):  
Ping-Sien Lin ◽  
Li-Wen Yang ◽  
C Hsein Juang

This paper presents the result of plate-load tests conducted on a gravelly cobble deposit in Taichung Basin, Taiwan. The geologic formation of the gravelly cobble deposit makes it very difficult to obtain large undisturbed samples for laboratory testing. These field tests provide an opportunity to examine the applicability of existing theories on bearing capacity and subgrade reaction in this geologic formation. The modulus of subgrade reaction is of particular importance in the local practice of designing high-rise buildings on mat foundations. The results of the plate-load tests on this soil deposit are analyzed and discussed.Key words: plate-load test, gravelly cobble deposit, modulus of subgrade reaction, bearing capacity.


2019 ◽  
Vol 14 (1) ◽  
pp. 37-57
Author(s):  
Yang Zhang ◽  
Pavana Vennapusa ◽  
David Joshua White

There are plenty of in situ tests available to examine pavement foundation performance regarding stiffness and support conditions. This study evaluates several in situ tests of the stiffness and support conditions of concrete pavement foundation layers. The principal objective of this study was to evaluate the outputs from Dynamic Cone Penetrometer tests and Falling Weight Deflectometer tests. The California Bearing Ratio from Dynamic Cone Penetrometer tests and the deflection data from Falling Weight Deflectometer tests were correlated to the design parameter – modulus of subgrade reaction k through correlations employed in pavement design manuals. Three methods for obtaining the k values were conducted, with the intent to evaluate which method provides the results most similar to the target value and whether the studied correlations are reliable. The back-calculated k values from Falling Weight Deflectometer deflections and the weak layer California Bearing Ratio correlated k values based on the Portland Cement Association method were close to the target value, while the California Bearing Ratio empirically correlated k based on the American Association of State Highway and Transportation Officials method presented values significantly higher than the target value. Those previously reported correlations were likely to overestimate the k values based on subgrade California Bearing Ratio values.


Author(s):  
Moshe Livneh ◽  
Noam A. Livneh

The use of a new quality control (QC) and quality assurance (QA) specification involving Dynamic Cone Penetrometer (DCP) testing in concert with conventional moisture and density testing is becoming more and more frequent in various parts of the world. The need for this additional testing is essential, as the regular in-situ density tests cannot alone ensure the compliance of the layers constructed with the compaction requirements. Recent analyses of the correlation between the DCP testing and the California Bearing Ratio CBR testing show that QC and QA DCP testing is adequate to verify compaction, stability and vertical uniformity in both cohesive and granular soils. Two examples of DCP usage in two Israeli earthwork projects, one of clayey soils and the other of silty-sand soils, indicate the benefits of this usage along with, though for the clayey example only, Falling Weight Deflectometer (FWD) testing.


Author(s):  
W. Spencer Guthrie ◽  
Tyler B. Young ◽  
Brandon J. Blankenagel ◽  
Dane A. Cooley

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 their sensitivity to curing time. The results indicated that although the SSG was more repeatable at one site, the CIST data were markedly more sensitive to curing time than the SSG data at all cement-treated sites during the first 72 h after construction. For this reason, the data suggest that the CIST offers greater overall utility than the SSG for monitoring early-age strength gain of CTB. Further research is needed to investigate appropriate thresholds and protocols for these testing methods that ensure adequate reliability of the collected data.


2020 ◽  
Vol 857 ◽  
pp. 179-187
Author(s):  
Mohammed Kadum Fakhraldin

Gypseous considered as problematic soils also gypseous soils are distributed all over the world, as well as in large areas of Iraq, including Al- Najaf city. Gypseous soils are characterized by high strength in dry conditions, but they collapse due to water infiltration process under constant head conditions. In this research, a field study investigates gypseous soils and the effect of soaked state on the bearing capacity and settlement of the gypseous soils are investigated. A site with a high percentage of gypsum (about 25%) was selected to perform plate load tests. The test was carried out in a natural and soaked state on the gypseous soils by plate load test with time-dependent. The results show the ultimate bearing capacity of gypseous soil from plate load test are decrease under the soaking condition and maximum settlement increase. The angle of internal friction (ø) of gypseous soil we obtained from the direct shear test is 47.620 for natural soil. The ultimate bearing capacity of gypseous soil was calculated from the Terzaqhi’s equation and the high difference between field tests and theoretical results.


2013 ◽  
Vol 712-715 ◽  
pp. 951-954
Author(s):  
Wang Chi ◽  
Yong Fu Xu ◽  
Ping Dong

The concrete-cored DCM pile is an kind of composite pile by inserting the inner concrete pile into the DCM column socket. In two test sites, plate load test is used to measure bearing capacity of concrete-cored DCM pile composite ground. Vertical stress of surrounding soil and DCM column socket are measured by pressure cells. The axial force of precast core pile can be obtained by steel stressmeters which welded on the reinforcing steel along depth. The field tests results show that, the bearing capacity of concrete-cored DCM pile composite ground is much larger than that of original soil. The development degree of concrete-cored DCM pile bearing capacity in composite foundation increases steadily during the loading process. Both concrete-cored DCM piles and surrounding soils play an important effect on the bearing capacity of composite foundation.


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