Roller Compacted Concrete Mixtures Research Articles

Mechanical properties and impact resistance of roller-compacted concrete containing polypropylene fibre

In this study, the effect of polypropylene fibre content on mechanical properties and impact resistance of roller-compacted concrete (RCC) was investigated. The polypropylene fibre was used as 0%, 0·25%, 0·50% and 0·75% per 1 m3 of concrete; thus, four different mixtures of RCC were prepared. The water content of those mixtures was determined using the maximum density method (soil compaction method). Optimum water content values for the maximum dry density of each RCC mixture were calculated with this approach. The compressive strength, splitting tensile strength, flexural strength, modulus of elasticity and impact resistance of RCC mixtures were determined at different ages. As a result of the experimental study, it was observed that the use of polypropylene fibre in RCC mixtures increases the water requirement and water/cement ratio. The mechanical properties of RCC mixtures containing polypropylene fibre decreased by 20% compared to the control mixture without polypropylene fibre. This phenomenon can be attributed to an increase in the water/cement ratio of the RCC mixture when using polypropylene fibre.

EFFECT OF CHEMICAL ADMIXTURES ON MECHANICAL PPROPERTIES OF ROLLER COMPACTED CONCRETE

This paper presents the experimental work carried out in order to evaluate the mechanical properties of roller compacted concrete mixtures in which a chemical admixture like super plasticizer is added in different dosages. The dosage percentages namely 0.5%, 0.75% and 1% by weight of cement have been added to RCC. Tests we performed to determine workability when RCC is in fresh state and mechanical properties when RCC is in hardened state. Workability like compaction factor test, vee bee test and slump test were conducted. Strength tests like compression strength, modulus of rupture and split tensile strength at 3days, 7days and 28days. Experimental investigation revealed that significant increases in strengths were observed in RCC with increase in super plasticizer dosage addition. Also workability of concrete was increased with increase in SP dosage.

A New Method of Rapid Measurement Representing the Workability of Roller Compacted Concrete and the Application

A new test method using moisture rate to represent workability indicators of dry-hard mixture is introduced in order to test the control indicators of VC value in the construction of roller compacted concrete rapidly. In view of the complexity of the impact of proportional difference on VC value and moisture rate, this paper carries out field tests of roller compacted concrete in Guoduo hydropower station of Tibet. A simplified linear quantitative model formula of VC value and moisture rate at the construction site is established based on determined aggregate grading, admixture, additive type and the amount of admixture of roller compacted concrete mixture, providing conditions for the rapid and accurate measurement of construction quality indicators of roller compacted concrete.

Laboratory Evaluation and Field Construction of Roller-Compacted Concrete for Testing under Accelerated Loading

The Louisiana Department of Transportation and Development has seen a rapid decline of low-volume roadway serviceability in recent years as a result of oil and gas exploration within the Fayetteville Shale Play near Shreveport, Louisiana. Similar results are expected on the low-volume roadway network within the Tuscaloosa Shale Play, north of Baton Rouge, Louisiana, as exploration expands. The objectives of this research were to determine appropriate proportions of roller-compacted concrete mixture for the construction of accelerated loading test lanes and to document field construction activities. Concrete samples were produced with four cement contents to determine the effect of moisture and density; the samples were tested for compressive strength at 7 and 28 days of age. The field testing included nuclear density testing, thickness measurements, and field-prepared compressive strength specimens. A walking profiler was used to determine the international roughness index (IRI). All laboratory-produced mixtures exceeded a compressive strength of 4,000 pounds per square inch (psi). When the desired surface characteristics and density were considered, 450 lb/yd3 was chosen as the minimum cementitious content for the construction of the test lanes. The field construction results showed that the speed of construction affected the density, the IRI, and the surface characteristics. An increased speed of construction yielded a rougher surface texture (an increased IRI between 360 and 620 in./mi) and slightly lower densities. The compressive strengths were still adequate and exceeded 4,500 psi at 28 days old. On the basis of the field results, IRI values in the 100- to 130-in./mi range and compressive strengths exceeding 5,000 psi may be expected in a full-scale roadway construction effort.

Construction of Roller-Compacted Concrete Pavement in the Fayetteville Shale Play Area, Arkansas

In 2012, roller-compacted concrete (RCC) pavement was used to rehabilitate a deteriorated section of roadway in the Fayetteville Shale Play Area (FSPA), Arkansas. As the result of recent heavy truck traffic related to natural gas exploration efforts in Arkansas, the FSPA has experienced significant pavement distresses that typical maintenance activities cannot sufficiently address. RCC pavement was selected as a potential solution to repair failing pavements in this area because that pavement could be constructed more quickly than conventional concrete pavements and could provide adequate structure for truck traffic. Two sections of RCC pavement were constructed on a rural, two-lane highway. The first was a 7-in. section placed on a cement reconstructed base course, and the second was an 8-in. section placed as an overlay. The RCC mixture contained a nominal, maximum aggregate size of ¾ in. and was designed to meet a minimum, 28-day compressive strength of 5,000 psi. Although some difficulties were encountered during the construction process, the final product was considered successful. Low initial strengths in Section 1 were believed to be caused by a combination of low temperatures and the presence of fly ash in the mix. Fly ash was removed from the mix design before the construction of Section 2 began, and the strength characteristics were much improved. Diamond grinding was used to ensure surface smoothness; this treatment resulted in an average International Roughness Index value of 69.5. After 6 months, a distress survey was performed in which minimal cracking was found. Minor surface distresses, including popouts and deterioration at construction joints, were noted.

Fracture Characterization of Roller Compacted Concrete Mixtures with Blast Furnace Slag and Industrial Sand

The global energy crisis and growing environmental concerns have prompted manufacturers in general to intensify their efforts to reuse the by-products and wastes they generate. In metallurgy, steel production generates dross in the form of slag. In the present study, roller-compacted concrete (RCC) mixtures were prepared and the sand fraction was composed with industrial sand and granulated blast furnace slag. The influence of these different fine aggregates was analyzed based on the compaction parameters (moisture and dry unit weight), indirect tensile strength, flexural strength, and modulus of elasticity. Toughness and fracture tests were carried out and R-curve was determined for the mixtures. It was found that the RCC mixtures containing slag required larger amounts of water for compaction, presented drops in tensile strength and modulus of elasticity as well as increased the mean values of propagation energy in little amount. Both the reference RCC and the slag RCC presented a consistently upward R-curve and, in absolute values, showed a better R-curve and KR performance than conventional and high-strength concretes previously studied in the literature. This is very important for paving purposes since a material with such a behavior shows greater resistance to catastrophic crack propagation, thus extending the service life of pavement layers.

Influences of mixture composition on properties and freeze–thaw resistance of RCC

The paper reports a series of lab investigations carried out on roller compacted concrete (RCC) mixtures containing a wide range of cement contents (100 and 450 kg/m 3). The key objectives were to appreciate the effects of variations in the cement content and air entrainment on basic physical, mechanical properties and freeze–thaw (F–T) resistances of RCC mixtures. The Vebe consistency, moisture–density relations, water absorption, permeable voids, compressive strength, and F–T resistances of comparable mixes were evaluated. Physical and mechanical properties indicated a significant deviation from the behavior shown by conventional concrete. Air entrainment was found to be affecting the strength and F/T durability of the mixes. Further analysis shows wide range applications of RCC in various pavement applications.

Prediction and Measurement of the Bending Strength of the RCC

The present work deals with the prediction, through models and experimental evaluation, of the bending strength of roller compacted concrete (RCC) for pavement applications. This concrete was manufactured using low cement proportioning (150 to <TEX>$250\;kg/m^3$</TEX>). The characterization of hardened RCC was carried out by experimental measurements of bending strengths. The predictions of these characteristics were achieved using empirical models. Comparison, of the values found in experiments with those empirically obtained, was made in order to choose and to propose the adapted and the most reliable models of prediction. The study showed that the bending strengths of the RCC mixture, experimentally found, can be also identified by models.

Roller-Compacted Concrete Mix Design Procedure with Gyratory Compactor

Roller-compacted concrete (RCC) pavements are durable and can be built rapidly and economically. In previous research, the gyratory compactor has proved to be a reliable instrument and overcome the drawbacks of other methods used to mold laboratory and field samples. Work is under way by different organizations in Canada, Japan, and the United States to improve mix design procedures for RCC. One procedure widely used for RCC pavements was developed by the U.S. Army Corps of Engineers. This research investigated improving mixture proportioning of RCC by using a gyratory compactor. Previous research suggested that the gyratory compactor could be used effectively to produce RCC test samples for both compressive and splitting tensile strength. An RCC mix design procedure using the gyratory compactor can benefit many transportation agencies because it provides a reliable way to evaluate the strength and density of RCC mix designs. Results for several RCC mixtures compacted to different densities are presented, along with comparisons with modified Proctor test results. Using the gyratory compactor to design better RCC mixtures might lower the costs and improve the reliability of RCC pavements.

Drying Shrinkage of Roller-Compacted Concrete for Pavement Applications

This paper reported the results of a laboratory investigation of the drying shrinkage of roller-compacted concrete (RCC) for pavement applications. The aggregate grading and moisture content of nine RCC mixtures were varied, and the drying shrinkage measured according to the procedures described in ASTM C 357, with some modifications. The 28-day drying shrinkage results of the mixtures ranged from 8 to 0.00033, with an overall average of 0.00015. The combined effects of moisture content and aggregate grading on the drying shrinkage were statistically significant, while the individual effects of moisture content or aggregate grading were not statistically significant. A regression model for predicting the 28-day drying shrinkage of RCC from the relative aggregate grading and moisture content was developed from the data, with a multiple correlation coefficient of 67%. The ACI Committee 209 model for predicting the drying shrinkage of concrete with time compared favorably with the RCC drying shrinkage data.

Frost Resistance of Roller-Compacted High-Volume Fly Ash Concrete

Laboratory investigations were performed to design four high-volume fly ash roller-compacted concrete mixtures. The amount of fly ash was fixed at 63% of the total cementitious material. Two mixtures (one air-entrained and one non-air-entrained) had a cementitious material content of 12% (as a proportion of the total mass of dry materials), and two mixtures (one air-entrained and one non-air-entrained) had a cementitious material content of 15%. The apparatus used to prepare the cylindrical specimens required for the tests was specifically designed for this purpose. In this apparatus, the concrete is placed in a cylindrical mold that is vibrated laterally while a longitudinal compressive force is applied to the concrete. Each mixture was tested for strength, absorption, permeability, determination of the air-void characteristics, and frost resistance. The frost resistance of air-entrained concretes (tested according to Procedure A of ASTM Standard C 666) was found to be very good, irrespective of the cementitious material content. These concretes contained only a small number of irregularly shaped compaction air voids. The value of the air-void spacing factor was 250 ± 5 μm for the air-entrained concretes, and only slightly higher at 309 μm and 393 μm for the non-air-entrained concretes. The latter concretes also showed adequate frost resistance. Notwithstanding these conditions, the use of air entrainment is recommended for roller-compacted, high-volume fly ash concretes.