scholarly journals POTENTIAL USE OF CINDER GRAVEL AS AN ALTERNATIVE BASE COURSE MATERIAL THROUGH BLENDING WITH CRUSHED STONE AGGREGATE AND CEMENT TREATMENT

2019 ◽  
Vol 10 (2) ◽  
pp. 101-112
Author(s):  
M. Seyfe ◽  
A. Geremew
Keyword(s):  
Compressive Strength ◽  
Mechanical Test ◽  
Crushed Stone ◽  
Crushed Rock ◽  
Sieve Analysis ◽  
Course Materials ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
Flakiness Index

Cinder gravels are pyroclastic materials associated with recent volcanic activity which occur in characteristically straight sided cone shaped hills. The aim of this study was to use this marginal material which is abundantly available in many parts of Ethiopia by modifying their properties through mechanical blending and chemical stabilization. Results of physical and mechanical test conducted on cinder gravel samples prove their marginality to be used as base course materials especially for highly trafficked roads. An experimental investigation were carried by blending cinder gravels with conventional crushed stone bases course material, Crushed Stone Aggregate (CSA), in proportions of cinder/ Crushed Stone Aggregate (CSA) (10/90, 20/80, 30/70, 40/60 and 50/50) and treating with 6. 8 and 10% of cement. According to results of sieve analysis, Aggregate crushing value (ACV), flakiness index and California Bearing Ratio (CBR), 30% of Crushed Stone Aggregate (CSA) can be replaced by cinder gravels for use as Fresh, crushed rock (GB1) material and for cement treated cinder gravels adding 6% and 8% cement make them suitable for use as Stabilized base course (CB2) and (CB1) base course materials respectively, referring to their 14 day compressive strength as determined by Unified compressive strength test(UCS) test.

Using Geogrids for Base Reinforcement as Measured by Falling Weight Deflectometer in Full-Scale Laboratory Study

1998 ◽  
Vol 1611 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Thomas C. Kinney ◽  
Danielle Stone ◽  
John Schuler
Keyword(s):  
Design Procedure ◽  
Pavement Design ◽  
Silty Sand ◽  
Crushed Rock ◽  
Falling Weight Deflectometer ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
Sand And Gravel ◽  
Falling Weight

A model road was constructed in a laboratory. The road consisted of asphalt over a crushed rock base and a silty sand and gravel subbase. The silty sand and gravel were placed in a very loose state to simulate a thaw-weakened, poor-quality subbase. The water table was kept at 152 mm (6 in.) below the bottom of the asphalt. The model road was divided into three sections. A geogrid was installed at the bottom of the base course material in two of the test sections, and the third was left as a control section. A falling weight deflectometer was used to measure the dynamic response of the pavement structure. The traffic benefit ratio is defined as the expected life (equivalent single-axle loads) of one section divided by the expected life of another section. The Alaska Department of Transportation and Public Facilities asphalt pavement design procedure and the NCHRP pavement design procedure were used to compare the test sections. The results from the two procedures were very similar. By using either procedure, the life of the pavement with respect to reinforcement was on the order of 2 to 4, depending on the type of grid and the depth of base course material.

scholarly journals Evaluation of Cement and Bitumen Emulsion on Strength Characteristics of Native South African Granular Soil as Base Course Material

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Oladapo S Abiola ◽  
Reece Wilson ◽  
Anthony Barnard ◽  
Shaun Hattingh ◽  
William K Kupolati ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
South African ◽  
Unconfined Compressive Strength ◽  
Base Layer ◽  
Bitumen Emulsion ◽  
Base Course Material ◽  
Course Material ◽  
Indirect Tensile ◽  
Base Course

Pavement rehabilitation where the material in the existing pavement is recycled in-situ with bitumen will sustain the environment with conservation of natural aggregates, reduction in noise, dust emission and traffic disruption. This study investigate the effects of a native South African granular material stabilized with cement and bitumen emulsion as a base layer in pavement construction. The material stabilized with cement-bitumen emulsion (2-3%) was subjected to Unconfined Compressive Strength (UCS) and Indirect Tensile Strength (ITS) tests for 1, 4, 7 and 28 days curing. The UCS and ITS requirement was evaluated with respect to a base layer for design traffic application of less than six million equivalent single axles. The results of UCS and ITS tests for the stabilized material showed improved strength and have the potential for use as a base course material for the design traffic. The result revealed that 2.5% cement and bitumen emulsion meets the minimum strength characteristics for the base layer. Relative to 2% cement and 2% bitumen emulsion, ITS obtained for 4 and 7 days of curing increased approximately by 24%, 41% and 24%, 53% respectively. Models for UCS in terms of ITS was developed for cement and bitumen emulsion which will make one test among the two sufficient to indicate the strength of cement and bitumen emulsion stabilized materials at the mix design level. Bitumen stabilization is a quick construction method, with lower cost than reconstruction and good for rehabilitation. Keywords— bitumen emulsion, cement, granular, indirect tensile strength unconfined compressive strength. 

Freezing-induced water migration in compacted base-course materials

2008 ◽  
Vol 45 (7) ◽  
pp. 895-909 ◽  
Author(s):  
J.-M. Konrad
Keyword(s):  
Water Source ◽  
Degree Of Saturation ◽  
Coarse Grained ◽  
Frost Heave ◽  
Freezing Process ◽  
Course Materials ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
External Water

Ramped-freezing tests were conducted on three base-course materials with fines contents of less than 7% and compacted at different initial states but always at degrees of saturation near or well below 60%. Three different quarries were studied. The natural fines from crushed gneiss with biotite, limestone, and monzonite were all frost susceptible. Frost heave was relatively small, but significant water intake occurred in all samples during freezing with access to an external water source, regardless of initial saturation level. The frost susceptibility of coarse-grained soils cannot be solely evaluated with respect to frost heave but needs also to consider the amount of water drawn to the freezing front during the freezing process and the consequences of this water during thaw. The normalized heave of the base-course layer of pavements is a practical and efficient indicator of the frost susceptibility of the base-course aggregates. If it is larger than 1%, the base-course material can be considered as frost susceptible leading to a significant increase in the degree of saturation once frozen. Current base-course material specifications based solely on grain-size distribution are not adequate to differentiate materials that are nonfrost susceptible from those that are frost susceptible. Hence, an additional criterion based on the fines frost susceptibility should be considered.

scholarly journals EFFECTS OF FREEZE-THAWING ON BEARING CAPACITY OF GRANULAR BASE COURSE MATERIAL

2012 ◽  
Vol 68 (3) ◽  
pp. I_115-I_122
Author(s):  
Shinichiro KAWABATA ◽  
Tatsuya ISHIKAWA ◽  
Takumi MURAYAMA ◽  
Shuichi KAMEYAMA
Keyword(s):  
Bearing Capacity ◽  
Base Course Material ◽  
Course Material ◽  
Base Course ◽  
Granular Base
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