Study on mechanical properties testing of highway concrete pavement construction machinery materials

Author(s):  
Wentao Huo
Author(s):  
Yoon-Ho Cho ◽  
Terry Dossey ◽  
B. Frank Mccullough

The effect of coarse aggregate on pavement performance has been attributed to the volume of aggregate used in pavement construction. The different patterns of crack development for limestone (LS) and siliceous river gravel (SRG) are a typical example of aggregate-induced variable performance in continuously reinforced concrete pavement (CRCP). An attempt was made to find a reasonable solution for pavements with SRG. As a way to solve the performance problem observed from the SRG pavement, a blended aggregates mixture was suggested. Laboratory and field tests were performed to check the feasibility of their application in pavements. From the laboratory test, a 50:50 blending ratio was suggested after considering the effect on tensile strength and thermal coefficient of expansion. Field test sections were also constructed to verify previous performance observations for the two aggregates and to provide performance data for new variables such as blended aggregates and special curing methods. Unexpectedly, the blended mixture did not improve the performance of SRG pavement; rather it experienced worse cracking than SRG alone. A controlled experiment with additional field test sections is needed to verify or disprove this finding. The only definitive finding was that selection of aggregate in the concrete pavement is a vital consideration for the design of the pavement. The CRCP8 analytical program reasonably predicted crack spacing for both SRG and LS pavements, predicting mean crack spacing of 0.99 m (3.25 ft) for SRG and 1.98 m (6.41 ft) for the limestone. These values are somewhat below the actual spacing observed at 100 days. Data collected after the first winter period will be required to calibrate the program.


Author(s):  
Robert Otto Rasmussen ◽  
Steven M. Karamihas ◽  
William R. Cape ◽  
George K. Chang ◽  
Ronald M. Guntert

2011 ◽  
Vol 314-316 ◽  
pp. 1210-1213
Author(s):  
Fang Po Li ◽  
Yong Gang Liu ◽  
Wang Yong

The failure cause of Φ127mm G105 IEU drill pipe upset was investigated through mechanical properties testing, optical morphologies and fracture surface analysis. The result show that drill pipe upset’s failure reason is the elephant hide and decarburization layer in its out-surface caused by improper upset treatment in forging process. Elephant hide and decarburization layer existing in drill pipe upset changed seriously reduced its strength and fatigue property. Under the effect of alternating stresses, the crack first initiated from the deepest position of elephant hide and developed quickly. In the end, it leaded the drill pipe to early piecing failure.


Sign in / Sign up

Export Citation Format

Share Document