Composite concrete pavement for highways and streets with the enriched quarry limestone waste as a coarse aggregate for concrete of subbase and/or lower layer

Abstract

Composite concrete pavement includes the surface course of normal concrete and subbase and / or lower layer of concrete with coarse aggregate defined as enriched limestone waste of grading intermediate between the coarse and fine aggregates. Specified compressive strength and modulus of rupture of this concrete amount up to 5,000 and 750 psi, respectively. Coarse aggregate of this concrete is enriched by-product of manufacture of crushed limestone of regular sizes. As a raw material for enrichment it should be coarser than 9.5 mm and finer than 4.75 mm. The amount of aggregate finer than 4.75 mm as a part of the total weight of aggregate should be not less than 1 / 3 before enrichment and close to but not exceed 2 / 3 in aggregate bin. The use of this very cheap and efficient concrete for composite concrete pavement allows reduction of initial cost of construction of this pavement and makes it more competitive as compared with asphalt pavement.

Description

REFERENCE TO RELATED APPLICATION[0001] Provisional Patent Application No. 60 / 446408 Filing Data Feb. 11, 2003FEDERALLY SPONSORED RESEARCH[0002] Not ApplicableSEQUENCE LISTING PROGRAM[0003] Not Applicable[0004] 1. Field of Invention[0005] Present invention relates to the design and construction of highway and street concrete pavements.[0006] 2. The Prior Art[0007] Composite concrete pavements with surface course of normal concrete and subbase or lower layer of lean concrete are used widely in the US building practice to reduce the cost of pavement. The design procedure of Portland Cement Association Engineering Bulletin (Thickness Design for Concrete Highway and Street Pavements, Portland Cement Association, EB 109P) indicates a thickness for two-layer concrete pavement equivalent to a given thickness of normal concrete. Lean concrete of modulus of rupture (MR) in the range from 150 to 450 psi for subbase and lower layer monolithic with normal concrete of surface course is taken for ...

AI Technical Summary

Benefits of technology

0026] Concrete of specified compressive strength and modulus of rupture up to 5,000 more than 750 psi, respectively, with enriched limestone waste as coarse aggregate is very cheap and efficient. The use of this concrete for composite concrete pavement means considerable reduction of initial cost of construction this pavement and increase of competitiveness as compared with asphalt pavement.

0027] Moreover, the use of concrete with this coarse aggregate allows very profitable utilization of great deposits of crushed limestone finer than 9.5 mm usually estimated as limestone quarry waste and especially aggregate finer than 4.75 mm. In so doing the volume of utilized aggregate finer than 4.75 mm should constitutes at least 1 / 3 of the utilized volume of aggregate finer than 9.5 mm. Utilization of limestone waste enables to reduce quarrying of high-quality aggregate with corresponding conservation of environment.

Problems solved by technology

Handling and transportation of enriched limestone waste from a quarry to the aggregate bin of a concrete plant causes inevitable breakdown of aggregate.

Due to weather effects and other impacts such as loading and discharge, grading of enriched limestone waste may become unpredictable.

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