A compleat treatise of the gravel and stone : wherein all their symptoms, causes and cures, are mechanically accounted for ... /

Mode of access: Internet.

Specifications for the bituminous surface treatment of gravel and crushed stone surfaces, subclass A-1.

Mode of access: Internet.

Specifications for the bituminous surface treatment of gravel and crushed stone surfaces, subclass A-3 (Liquid and powdered asphalt) : effective May 15, 1939.

Mode of access: Internet.

Large scale experiments on gravel and mixed beaches: Experimental procedure, data documentation and initial results

This paper provides information on the experimental set-up, data collection methods and results to date for the project Large scale modelling of coarse grained beaches, undertaken at the Large Wave Channel (GWK) of FZK in Hannover by an international group of researchers in Spring 2002. The main objective of the experiments was to provide full scale measurements of cross-shore processes on gravel and mixed beaches for the verification and further development of cross-shore numerical models of gravel and mixed sediment beaches. Identical random and regular wave tests were undertaken for a gravel beach and a mixed sand/gravel beach set up in the flume. Measurements included profile development, water surface elevation along the flume, internal pressures in the swash zone, piezometric head levels within the beach, run-up, flow velocities in the surf-zone and sediment size distributions. The purpose of the paper is to present to the scientific community the experimental procedure, a summary of the data collected, some initial results, as well as a brief outline of the on-going research being carried out with the data by different research groups. The experimental data is available to all the scientific community following submission of a statement of objectives, specification of data requirements and an agreement to abide with the GWK and EU protocols. (C) 2005 Elsevier B.V. All rights reserved.

Evaluation and Testing of a Lightweight Fine Aggregate Concrete Bridge Deck in Buchanan County, Iowa, TR-648, 2016

Internal curing is a relatively new technique being used to promote hydration of Portland cement concretes. The fundamental concept is to provide reservoirs of water within the matrix such that the water does not increase the initial water/cementitious materials ratio to the mixture, but is available to help continue hydration once the system starts to dry out. The reservoirs used in the US are typically in the form of lightweight fine aggregate (LWFA) that is saturated prior to batching. Considerable work has been conducted both in the laboratory and in the field to confirm that this approach is fundamentally sound and yet practical for construction purposes. A number of bridge decks have been successfully constructed around the US, including one in Iowa in 2013. It is reported that inclusion of about 20% to 30% LWFA will not only improve strength development and potential durability, but, more importantly, will significantly reduce shrinking, thus reducing cracking risk. The aim of this work was to investigate the feasibility of such an approach in a bridge deck.

Evaluation of Carbonate Aggregate Using X-Ray Analysis, HR-266, 1989

Iowa has more than 13,000 miles of portland cement concrete (PCC) pavement. Some pavements have performed well for over 50 years, while others have been removed or overlaid due to the premature deterioration of joints and cracks. Some of the premature deterioration is classical D-cracking, which is attributed to a critically saturated aggregate pore system (freeze-thaw damage). However, some of the premature deterioration is related to adverse chemical reactivity involving carbonate coarse aggregate. The objective of this paper is to demonstrate the value of a chemical analysis of carbonate aggregate using X-ray equipment to identify good or poor quality. At least 1.5% dolomite is necessary in a carbonate aggregate to produce a discernible dolomite peak. The shift of the maximum-intensity X-ray diffraction dolomite d-spacing can be used to predict poor performance of a carbonate aggregate in PCC. A limestone aggregate with a low percentage of strontium (less than 0.013) and phosphorus (less than 0.010) would be expected to give good performance in PCC pavement. Poor performance in PCC pavement is expected from limestone aggregates with higher percentages (above 0.05) of strontium.

Thermogravimetric Analysis of Carbonate Aggregate, HR-336, 1994

Research has shown that one of the major contributing factors in early joint deterioration of portland cement concrete (PCC) pavement is the quality of the coarse aggregate. Conventional physical and freeze/thaw tests are slow and not satisfactory in evaluating aggregate quality. In the last ten years the Iowa DOT has been evaluating X-ray analysis and other new technologies to predict aggregate durability in PCC pavement. The objective of this research is to evaluate thermogravimetric analysis (TGA) of carbonate aggregate. The TGA testing has been conducted with a TA 2950 Thermogravimetric Analyzer. The equipment is controlled by an IBM compatible computer. A "TA Hi-RES" (trademark) software package allows for rapid testing while retaining high resolution. The carbon dioxide is driven off the dolomite fraction between 705 deg C and 745 deg C and off the calcite fraction between 905 deg C and 940 deg C. The graphical plot of the temperature and weight loss using the same sample size and test procedure demonstrates that the test is very accurate and repeatable. A substantial number of both dolomites and limestones (calcites) have been subjected to TGA testing. The slopes of the weight loss plot prior to the dolomite and calcite transitions does correlate with field performance. The noncarbonate fraction, which correlates to the acid insolubles, can be determined by TGA for most calcites and some dolomites. TGA has provided information that can be used to help predict the quality of carbonate aggregate.

Coarse Aggregate Gradations for P.C. Concrete, MLR-94-8, 1995

The effect of coarse aggregate gradation and cement content on strength of concrete was studied. Concrete made of Iowa Department of Transportation Standard Mix C-3 and Aggregate Gradation No. 3 were selected as reference. C-3 proportions were used for mixes #1 and #2. C-3 mix with 10% reduction of the cement content was used for mix #3. C-3 mix with 20% reduction of the cement content was used for mix #4. On the other hand, mix #1 used coarse aggregate of Gradation No. 3, while mixes #2, #3, and #4 used coarse aggregate mix of 65% concrete stone and 35% 3/8 in. chips. It was found that strengths of portland cement concrete decrease with decreasing cement factor. On the other hand, 35% of chip replacement for coarse aggregate increases strengths of concrete. By replacing 35% of coarse aggregate with chips, one could reduce cement factor 10% and achieve equivalent strengths.

Structural Analysis of Aggregate Blends Using the SHRP Gyratory Compactor, MLR-95-8, 1996

The Iowa Department of Transportation (IDOT) received a Strategic Highway Research Program (SHRP) gyratory compactor in December 1994. Since then IDOT has been studying the ability of the compactor to analyze fundamental properties of aggregates such as shape, texture, and gradation by studying the volumetrics of the aggregate blends under a standard load using the SHRP gyratory compactor. This method of analyzing the volumetrics of aggregate blends is similar to SHRP's fine aggregate angularity procedure, which analyzes void levels in noncompacted aggregate blends, which in turn can be used to evaluate the texture or shape of aggregates, what SHRP refers to as angularity. Research is showing that by splitting the aggregate blend on the 2.36-mm (#8) sieve and analyzing the volumetrics or angularity of the separated blend, important fundamental properties can be determined. Most important is structure (the degree and location of aggregate interlock). In addition, analysis of the volumes of the coarse and fine portions can predict the voids in the mineral aggregate and the desired asphalt content. By predicting these properties, it can be determined whether the combined aggregate blend, when mixed with asphalt cement, will produce a mix with structural adequacy to carry the designed traffic load.