Untreated aeolian sand base course for low-volume road proven by 50-year old road experiment

Netterberg, F; Elsmere, D

doi:10.17159/2309-8775/2015/v57n2a7

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…The Holocene climate history of the Indo-Gangetic plain shows a fabric of calcrete formation in older soils thereby precipitation of carbonates is common in the region (Srivastava, 2001). The hard duricrust is mostly formed in arid to semi-arid drier climatic conditions (Netterberg, 1980). As the thick calcrete layer is recorded at the bottom prior to 4.6 ka it is inferred that intense aridity began much earlier in CGP with intermittent variations in monsoonal pattern between ~4.6 and 4.2 ka.…”

Section: Discussionmentioning

confidence: 99%

Monitoring hydroecology and climatic variability since ~4.6 ka from palynological, sedimentological and environmental perspectives in an Ox-bow lake, Central Ganga Plain, India

Farooqui¹,

Khan²,

Agnihotri³

et al. 2023

The Holocene

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The Ganga-Sai River Interfluve contains several ox-bow lakes in the fertile Central Ganga plains (CGP). A ~2.20-meter deep sedimentary profile obtained near the Chandra Shekhar Azad bird sanctuary (Nawabganj lake-NL) of the CGP was studied to understand the evolution of the ecosystem and climate using pollen/spores, diatoms, testate amoebae, environmental magnetic data,and carbon and nitrogen isotopes. This sedimentary profile is chronologically well-constrained by five radiocarbon (14C) dates. Between 4.6 and 4.4 ka, the sandy sediment and pollen evidence for riparian forest, the absence of aquatic pollen and sponge spicules suggest scant water in the vicinity through the river channel. A semi-closed fluvial ecosystem between 4.4 and 4.2 ka is indicated by testate amoebae, sponge spicules and arboreal pollen. At least two intermittent warm conditions prevailed between 4.6 and 4.2 ka. Between 4.2 and 2.8 ka, high aquatic pollen, diatoms and testate amoebae indicate a lake ecosystem. By ~2.8–0.9 ka the gammoscleres from sponges formed during dry seasons indicate recharging during monsoon as the river shifted. Thereafter, agricultural pollen ( Brassica and Apiaceae) indicates a further shift in the lake boundary exposing land. The highly sandy texture, fluctuating δ13C, δ15N and magnetic mineral values indicate an unstable fluvio-lacustrine deposition inducing hydroecological changes influenced by intermittent about 5–6 humid and dry climatic conditions since ~4.6 ka to present. The calcrete layer in the bottom sediments shows high aridity in CGP between ~5 and 4.6 ka reaching the climax cold-dry event of ~4.2 ka recorded worldwide. The spectral analysis of palynological data from NL and the contemporary Barela Lake, reveals de Vries and Gleissberg cycles of low and high solar irradiance at centennial to multi-centennial scale during the Holocene. The impact on vegetation, sediment depositional dynamics, and shift in river channel was more rapid showing the dominance of ~200 years. periodicity post ~5 ka as compared to ~300 years of dominance prior to this. This centennial timescale is of great speculation for future climate predictions in CGP coupled with the anthropogenic forcings.

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Section: Discussionmentioning

confidence: 99%

Monitoring hydroecology and climatic variability since ~4.6 ka from palynological, sedimentological and environmental perspectives in an Ox-bow lake, Central Ganga Plain, India

Farooqui¹,

Khan²,

Agnihotri³

et al. 2023

The Holocene

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“…Previous studies have shown that the addition of cement, lime, and other cementing materials to aeolian sand can improve the compactness of aeolian sand and reduce its porosity, thus improving its compressive, shear, and tensile strength [ 6 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. At present, aeolian sand has been widely used in the preparation of mortar, concrete, and roadbed filler [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Strength Formation of Unfired Bricks Composed of Aeolian Sand–Loess Composite

Liu,

Guo,

Zhang

et al. 2024

Materials

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Aeolian sand and loess are both natural materials with poor engineering-related properties, and no research has been devoted to exploring aeolian sand–loess composite materials. In this study, we used aeolian sand and loess as the main raw materials to prepare unfired bricks by using the pressing method, along with cement, fly ash, and polypropylene fiber. The effects of different preparation conditions on the physical properties of the unfired bricks were investigated based on compressive strength, water absorption, and softening tests and a freeze–thaw cycle test combined with X-ray diffraction and scanning electron microscope analysis to determine the optimal mixing ratio for unfired bricks, and finally, the effects of fibers on the durability of the unfired bricks were investigated. The results reveal that the optimal mixing ratio of the masses of aeolian sand–loess –cement –fly ash–polypropylene fiber–alkali activator–water was 56.10:28.05:9.17:2.40:0.4:0.003:4.24 under a forming pressure of 20 MPa. The composite unfired bricks prepared had a compressive strength of 14.5 MPa at 14 d, with a rate of water absorption of 8.8%, coefficient of softening of 0.92, and rates of the losses of frozen strength and mass of 15.93% and 1.06%, respectively, where these satisfied the requirements of environmentally protective bricks with strength grades of MU10–MU15. During the curing process, silicate and sodium silicate gels tightly connected the particles of aeolian sand and the loess skeleton, and the spatial network formed by the addition of the fibers inhibited the deformation of soil and improved the strength of the unfired bricks.

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“…Moreover, filling the DS road base in irrigation area, paddy field, and soft foundation exerts a good effect on blocking capillary water and strengthening the stability of road base. Netterberg et al [16] conducted a long-term observation on the test section of DS road base in South Africa and found that the road structure can maintain stability. Similarly, Song et al [17] applied 6% DS instead of fine aggregate to the CSM and demonstrated that it could meet the road performance of the base mixture through the indoor test and test section tracking detection.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Cement Stabilized Base with Recycled Aggregate and Desert Sand

Liu,

Qin,

Yang

2024

Preprint

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This paper mainly explores the feasibility of using desert sand (DS) and recycled aggregate in cement stabilized base. Recycled coarse aggregate (RCA) and DS serve as the substitutes of natural coarse and fine aggregates, respectively, in cement stabilized base. A four-factor and four-level orthogonal test is designed to analyze the unconfined compressive strength, splitting tensile strength, and compressive resilient modulus. Furthermore, this paper investigates the effects of cement content, fly ash (FA) replacement rate, RCA replacement rate, and DS replacement rate on the road performance of cement stabilized base composing of RCA and DS. The test results reveal that the performance of cement stabilized base with partial RCA instead of natural coarse aggregate (NCA) and partial DS instead of natural fine aggregate satisfy the road use. Meanwhile, DS is beneficial to improve the strength of cement stabilized base. The correlation and microscopic analyses of the test results imply the feasibility of applying DS and recycled aggregate to cement stabilized base. It is hoped that this paper can offer a solid theoretical foundation for promoting the application of DS and recycled aggregate in road engineering.

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Untreated aeolian sand base course for low-volume road proven by 50-year old road experiment

Cited by 4 publications

References 6 publications

Monitoring hydroecology and climatic variability since ~4.6 ka from palynological, sedimentological and environmental perspectives in an Ox-bow lake, Central Ganga Plain, India

Monitoring hydroecology and climatic variability since ~4.6 ka from palynological, sedimentological and environmental perspectives in an Ox-bow lake, Central Ganga Plain, India

Mechanism of Strength Formation of Unfired Bricks Composed of Aeolian Sand–Loess Composite

Investigation on Cement Stabilized Base with Recycled Aggregate and Desert Sand

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