The Use of Fly Ash in Highway Construction, HR-1031, Progress Report, 1986

In 1982 the Iowa DOT allowed a successful bidder the option of submitting materials and proportions using fly ash to produce a portland cement concrete (PCC) paving mixture to meet a specified compressive strength. The contractor, Irving F. Jensen, received approval for the use of a concrete mixture utilizing 500 lbs. of portland cement and 88 lbs. of fly ash as a replacement of 88 lbs. of portland cement. The PCC mixture was utilized on the Muscatine County US 61 relocation bypass paved as project F-61-4(32)--20-70. A Class "C" fly ash obtained from the Chillicothe electric generating plant approximately 100 miles away was used in the project. This use of fly ash in lieu of portland cement resulted in a cost savings of $64,500 and an energy savings of approximately 16 billion BTU. The compressive strength of this PCC mixture option was very comparable to concrete mixtures produced without the use of fly ash. The pavement has been performing very well. The substitution of fly ash for 15% of the cement has been allowed as a contractor's option since 1984. Due to the cost savings, it has been used in almost all Iowa PCC paving since that time.

Ammonium Phosphate/Fly Ash Road Base Construction, HR-294, Construction Report, 1987

The objective of this research project was to evaluate the construction and service performance of ammonium phosphate/fly ash (APFA) treated base courses of crushed fines and/or unprocessed sand. Specific test results related to construction of the test sections were included in the 1987 construction report by Iowa State University. The performance of the experimental sections is dealt with in this final report. This 1986 project demonstrated that in all cases the control sections utilizing a Type B base experienced dramatically less cracking in the surface than the APFA treated base sections. The cost per mix and subsequent surface maintenance costs for the APFA base sections, especially those having a substantial amount of limestone, were higher than the Type B base control sections. This type of construction may prove to be economical only when petroleum product costs escalate.

Performance of Nongrouted Thin Bonded PCC Overlays, Construction Report, HR-291, 1986

The Iowa road system has approximately 13,000 miles of Portland Cement Concrete Pavements, many of which are reaching the stage where major rehabilitation is required. Age, greater than anticipated traffic, heavier loads and deterioration related to coarse aggregate in the original pavement are some of the reasons that these pavements have reached this level of distress. One method utilized to rehabilitate distressed or underdesigned PCC pavements is the thin bonded Portland Cement Concrete overlay. Since the introduction of thin bonded overlays on highway pavements in 1973, the concrete paving industry has made progress in reducing the construction costs of this rehabilitation technique. With the advent of the shotblast machine, surface preparation costs have decreased from over $4.00 per square yard to most recently $1.42 per square yard. Other construction costs, including placement, grouting and sawing, have also declined. With each project, knowledge and efficiency have improved.

Iowa Development of Rubblized Concrete Pavement Base Mills County, Construction Report, HR-315, 1990

The concept of rubblizing existing concrete pavement prior to the placement of an asphaltic cement concrete overlay has been around for several years and, in fact, has been tried successfully in the states of New York, Michigan, and Ohio. With available construction and maintenance dollars usually not meeting the demands of the needed work, much of the necessary rehabilitation of existing Portland cement concrete pavements is not being completed when it would be most beneficial. Research project HR-315, "Iowa Development of Rubblized Concrete", has been undertaken to determine the effects of rubblized concrete pavement base as it affects the cracking pattern and longevity of the ACC overlay.

Pavement Surface on Macadam Base, Adair County, HR-209, Construction Report, 1980

The objectives were to determine the feasibility and performance of this type of construction and to determine if the macadam base is effective in reducin9or eliminating D-cracking deterioration.

Alternative Flexible Overlays, HR-229, Construction Report, 1983

The object of this research project is to construct and evaluate several bituminous concrete base overlays with various high penetration bituminous products which have the potential to reduce future maintenance and construction costs. In September of 1981 nine different bituminous test sections were constructed on Osceola County roads A-34 and A-46 east of Ashton. Asphalt binders used were AC-5 asphalt cement, SC-800 liquid asphalt, MC-3000 cutback asphalt, CSS-1 emulsion and HFMS-2 emulsion. Aggregate for four of the test sections consisted of salvaged bituminous pavement and new aggregate combined. Each section was road mixed using a different binder arid placed 2-1/4" thick with a motor patrol. The other five test sections consisted of an AC-5 Type B asphalt concrete control section and four plant-mixed, cold-laid bituminous concrete overlay sections using new aggregate. The material was mixed in a continuous drum mix plant and laid with a full width paver.

Construction. Participation des employeurs. [1954.] 2e édition

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Construcció i explotació d'un magatzem de dades per a l'anàlisi d'informació sobre trànsit rodat de vehicles

Aquest treball de fi de carrera proposa la construcció i explotació d'un magatzem de dades o data warehouse amb l'objectiu d'analitzar la informació relativa a l'evolució del parc de vehicles a Catalunya.

Construction mechanisms and thermal evolution of upper crustal intrusions : the Saint-Jean-du-Doigt bimodal intrusion (Brittany, France)

Understanding the emplacement and growth of intrusive bodies in terms of mechanism, duration, ther¬mal evolution and rates are fundamental aspects of crustal evolution. Recent studies show that many plutons grow in several Ma by in situ accretion of discrete magma pulses, which constitute small-scale magmatic reservoirs. The residence time of magmas, and hence their capacities to interact and differentiate, are con¬trolled by the local thermal environment. The latter is highly dependant on 1) the emplacement depth, 2) the magmas and country rock composition, 3) the country rock thermal conductivity, 4) the rate of magma injection and 5) the geometry of the intrusion. In shallow level plutons, where magmas solidify quickly, evi¬dence for magma mixing and/or differentiation processes is considered by many authors to be inherited from deeper levels. This work shows however that in-situ differentiation and magma interactions occurred within basaltic and felsic sills at shallow depth (0.3 GPa) in the St-Jean-du-Doigt (SJDD) bimodal intrusion, France. This intrusion emplaced ca. 347 Ma ago (IDTIMS U/Pb on zircon) in the Precambrian crust of the Armori- can massif and preserves remarkable sill-like emplacement processes of bimodal mafic-felsic magmas. Field evidence coupled to high precision zircon U-Pb dating document progressive thermal maturation within the incrementally built ioppolith. Early m-thick mafic sills (eastern part) form the roof of the intrusion and are homogeneous and fine-grained with planar contacts with neighboring felsic sills; within a minimal 0.8 Ma time span, the system gets warmer (western part). Sills are emplaced by under-accretion under the old east¬ern part, interact and mingle. A striking feature of this younger, warmer part is in-situ differentiation of the mafic sills in the top 40 cm of the layer, which suggests liquids survival in the shallow crust. Rheological and thermal models were performed in order to determine the parameters required to allow this observed in- situ differentiation-accumulation processes. Strong constraints such as total emplacement durations (ca. 0.8 Ma, TIMS date) and pluton thickness (1.5 Km, gravity model) allow a quantitative estimation of the various parameters required (injection rates, incubation time,...). The results show that in-situ differentiation may be achieved in less than 10 years at such shallow depth, provided that: (1) The differentiating sills are injected beneath consolidated, yet still warm basalt sills, which act as low conductive insulating screens (eastern part formation in the SJDD intrusion). The latter are emplaced in a very short time (800 years) at high injection rate (0.5 m/y) in order to create a "hot zone" in the shallow crust (incubation time). This implies that nearly 1/3 of the pluton (400m) is emplaced by a subsequent and sustained magmatic activity occurring on a short time scale at the very beginning of the system. (2) Once incubation time is achieved, the calculations show that a small hot zone is created at the base of the sill pile, where new injections stay above their solidus T°C and may interact and differentiate. Extraction of differentiated residual liquids might eventually take place and mix with newly injected magma as documented in active syn-emplacement shear-zones within the "warm" part of the pluton. (3) Finally, the model show that in order to maintain a permanent hot zone at shallow level, injection rate must be of 0.03 m/y with injection of 5m thick basaltic sills eveiy 130yr, imply¬ing formation of a 15 km thick pluton. As this thickness is in contradiction with the one calculated for SJDD (1.5 Km) and exceed much the average thickness observed for many shallow level plutons, I infer that there is no permanent hot zone (or magma chambers) at such shallow level. I rather propose formation of small, ephemeral (10-15yr) reservoirs, which represent only small portions of the final size of the pluton. Thermal calculations show that, in the case of SJDD, 5m thick basaltic sills emplaced every 1500 y, allow formation of such ephemeral reservoirs. The latter are formed by several sills, which are in a mushy state and may interact and differentiate during a short time.The mineralogical, chemical and isotopic data presented in this study suggest a signature intermediate be¬tween E-MORB- and arc-like for the SJDD mafic sills and feeder dykes. The mantle source involved produced hydrated magmas and may be astenosphere modified by "arc-type" components, probably related to a sub¬ducting slab. Combined fluid mobile/immobile trace elements and Sr-Nd isotopes suggest that such subduc¬tion components are mainly fluids derived from altered oceanic crust with minor effect from the subducted sediments. Close match between the SJDD compositions and BABB may point to a continental back-arc setting with little crustal contamination. If so, the SjDD intrusion is a major witness of an extensional tectonic regime during the Early-Carboniferous, linked to the subduction of the Rheno-Hercynian Ocean beneath the Variscan terranes. Also of interest is the unusual association of cogenetic (same isotopic compositions) K-feldspar A- type granite and albite-granite. A-type granites may form by magma mixing between the mafic magma and crustal melts. Alternatively, they might derive from the melting of a biotite-bearing quartz-feldspathic crustal protolith triggered by early mafic injections at low crustal levels. Albite-granite may form by plagioclase cu¬mulate remelting issued from A-type magma differentiation.

Participation des employeurs à l'effort de construction. 1974, 15 septembre (Éd. mise à jour au..)

Collection : Journal officiel de la République française ; brochure 1002

Participation des départements et des communes aux sociétés d'économie mixte de construction . [Loi du 5 avril 1884, décrets et circulaires. Mise à jour au 1er mai 1957.]

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