These methods primarily address proper selection of optimum cement contents through laboratory testing and innovative construction techniques in the. Use ctfdb which is a mixture of aggregate, portland cement, and water. Minimizing reflective cracking in cementstabilized pavement. Cement treated base is oftentimes used in heavy civil construction applications such as highways, airports and wharfs. Ensure the application rate conforms to requirements. Cement based pavement materials ca s t r o ll e d n o w e a ri n g c o u r s e r e q ui re d w e a ri n g c o u r s e r e q ui r e d rollercompacted concrete conventional concrete soil cement flowable fill cement modified soil fulldepth reclamation cement treated cement content base water content. Cement treated base ctb is a mixedinplace or centralplantproduced material consisting of soilaggregate, cement, and water that creates a strong and durable stabilized roadway base. Ctb surface should be free of all dry, loose, and extraneous material. Ctb can be mixed inplace with onsite soils or mixed in a central plant or pugmill depending on the. The use of cement stabilized bases, such as soil cement, cement treated aggregate base, or fulldepth reclamation, actually reduces the occurrence of failure related cracking. Soil cement seminar ppt with pdf report study mafia. Cement treated base ctb is a general term that applies to an mixture of native soils andor manufactured aggregates with measured amounts of portland cement and water that is compacted and cured to form a strong, durable, frost resistant paving material.
This dissertation is brought to you for free and open access by the iowa state university capstones. Silica reacts violently with powerful oxidizing agents such as fluorine, boron trifluoride, chlorine trifluoride, manganese trifluoride, and oxygen difluoride yielding possible fire andor explosions. Removetake off immediately all contaminated clothing. This paper will look at the types and causes of reflective cracking in cement stabilized pavement bases and what techniques are available to minimize them for. Characterization and structural design of cementtreated base. Furnish uncontaminated materials of uniform quality that meet the requirements of the plans and specifications. Cementtreated base ctb is a general term that applies to an intimate mixture of native soils andor manufactured aggregates with measured amounts of portland cement and water that hardens after compaction and curing to form a strong, durable, frost resistant paving material. Suggested levels of inspection for typical cement treated base work activities are. The word will generally pertains to decisions or actions of the kansas department of transportation. Examples ogfrading requirements for subbase materials are given in thetable 62.
No pavement design guideline is presently available cement treated sub base. Dec 09, 2012 using the padfoot compactor to walk down the larger aggregate that the smooth drum cant after the cement was tilled into the base. The primary difference between ctb and soil cement is that ctb usually utilizes a graded aggregate instead of. Mixes containing 100%, 75% and 50% rap treated with portland cement of 0%, 2%.
The primary difference between ctb and soil cement is that ctb usually utilizes a graded aggregate instead of the native soils. In cementtreated base construction the objective is to obtain a thorough mixture of an aggregategranular material with the correct quantity of portland cement and enough water to permit maximum compaction. Bound cement treated base course, damage variable, fatigue damage, continuum damage mechanics 1 introduction cement treated base ctb is the product of soil cement stabilization technique by mixing a conventional road base material with a prescribed amount of cement, and water. Free reinforced concrete publications americas cement. Southern crushed concretes cementtreated base ctb is a mixture of crushed concrete combined with carefully measured amounts of cement that harden after compaction to form a durable paving material. Methodology 1 design procedure 2 cost comparison procedure 2 road mix selection of material two methods plant mix road mix inplace ainsitu method step 1.
Cementtreated free draining base how is cementtreated. Pdf laboratory investigation on the strength characteristics of. Cement treated base how is cement treated base abbreviated. Furnish water that is free of industrial waste and other objectionable material. A bituminous or portland cement concrete wearing course is placed on the ctb to complete the pavement structure. The goal of microcracking is to prevent severe, wide.
The portland cement association pca, founded in 1916, is the premier policy, research, education, and market intelligence organization serving americas cement manufacturers. A well designed, constructed, and properly maintained cement stabilized base will normally outlast several asphalt overlays, providing decades of low maintenance service. Improving longterm performance of cementtreated aggregate. To facilitate communication between the contractor and the engineer regarding quality control, equip the contractors testing facility with the following. Guide to cementtreated base ctb portland cement association 5420 old orchard road skokie, illinois 600771083 847. Abstract reclaimed asphalt pavement rap and granular base materials were collected from stockpiles in six txdot districts to evaluate the feasibility of using high rap content mixes for base course applications. This was based on the philosophy that a thicker section. Measurement by the cubic yard in final position and square yard is a plans quantity measurement. Factors that can influence shrinkage cracking in soil cement bases are. Interpretation of geotechnical properties of cement. Base the determination on an amount that will provide a complete membrane without appreciable thickness. Most problems with cementstabilized base layers in pavements stem from the fact that current design practices are based only on strength. Subbases may be constructed of granular materials, cement treated materials, lean concrete, or opengraded, highlypermeable materials, which may be stabilized or unstabilized. A soil cement base holds higher proportion of cement than cement converted soil.
The completed ctb must be adequately cured to both let the cement hydrate and to harden the cementaggregate mixture. Base course mix design criteria for cementtreated loess. Base course mix design criteria for cement treated loess kalankamary pily george iowa state university follow this and additional works at. In pca notes on aci 31811 building code, the emphasis is placed on howtouse the code incorporating discussions behind the code provisions and fully worked design solutions to real world problems. It is an economical and environmentally friendly pavement base option, as it utilizes local aggregates and onsite soils. This section provides guidelines for inspecting cement treated base ctb. Cementtreated base ctb is a strong, frostresistant base for a concrete or asphalt pavement wearing surface. Characterization and structural design of cementtreated base k.
Furnish water free of industrial wast es and other objectionable material. Cementtreated base will be measured by the ton, cubic yard, or square yard as a composite mixture of cement, flexible base, and recycled materials. Ctb consists of native soils, gravels, or manufactured aggregates blended with prescribed quantities of cement and water. A cement treated base is a mix of granular soil total or total material with portland cement and water. Standards for federal aviation specifying construction of. If the pccp in the contract is not specified as qcqa, bid item quality control testing ctb is not included as a bid item subsections 306. In charge of dean f gr dubte college iowa state university of science and technology. Nonpotable water shall not be used unless the requirements of aci 318. Compact the bottom course to at least 95% of the maximum density determined in accordance with tex121e, unless otherwise shown on the plans.
The work required for cement treated granular base and cement treated granular subbase is detailed in subsections 315. Cement treated base ctb is a strong base for both rigid or flexible pavements. Its slablike characteristics and beam strength are unmatched by granular bases that can fail when aggregate interlock is lost. Base course mix design criteria for cement treated loess by kalankamary pily george a dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of doctor of philosophy major subject. Compact subsequent courses treated under this item to at least 98% of the maximum density determined in accordance with tex121e, unless otherwise shown on the plans. Also implied in this language are shall, shall be, or similar words and phrases. The manual has been found to be also an invaluable aid to educators, contractors, materials and product manufacturers, building code authorities, inspectors, and others involved in the design. Portland cement treated materials shall consist of. Weakening and expansion of cementstabilized soils is due pri marily to sulfate, cement, and clay reactions instead of the sulfate and cement reactions that lead to the destruction of ordinary port land cements 6. The strength of cement treated aggregate base represented by california bearing ratio cbr and compressive strength with percent higher than those to base by 46% and 58% respectively. Also, the maintenancefree service life of projects that had not reached the point of. Construct vertical joints between new cement treated base and cement treated base that has been in place 4 hr. Bases and subbases for concrete pavement home fhwa. It is commonly used as an inexpensive pavement base for roads, streets, airports, and material handling areas.
Design a cement treated base ctb mixture meeting the requirements of the. Microcracking for reduced shrinkage in cementtreated base. Pavements now constructed in india with ctb are stronger than older granular base roads that have not been properly stabilized. Place the cementtreated base on a subgrade or base prepared in accordance. The strength of cement treated aggregate base represented by. Cement treated base ctb is an intimate mixture of aggregate material andor granular soils combined with measured amounts of portland cement and water that hardens after compaction and curing to form a durable paving material. Cement treated free draining base how is cement treated free draining base abbreviated.
Cement treated base safety data sheet according to federal register vol. Fatigue cracking, with its typical alligator pattern, is decreased because the stiff. S free, unrestrained shrinkage, and v poissons ratio. Mix and compact cement, water, and subgrade or base with or without asphalt concrete pavement in the roadway. This work consists of constructing a cement treated free draining base ctfdb on a prepared base course. The blend of materials in our cement treated base must cure adequately to allow the cement to hydrate and the mixture to harden. Pdf cementtreated base ctb is a nonconventional method used in road. Mix design mixing, gradation and experiment specimens containing various cementenious contents molded. Cement stabilization of soils foundation performance. For 10% cement treated soils pore pressures rose rapidly to confining pressure s resulting in zero effective confining pressure at failure. Ctb also allows for quick construction and therefore, lowers costs. Section 27, cement treated bases, of the standard specifications provides requirements for placing ctba mix of aggregate, portland cement, and water. To overcome this problem, the objective of present research work is to develop a pavement design chart using cement and. Policy and procedures manual for the certified inspection and testing cit.
Place successive base courses using the same methods as the first course. Obtain necessary certificates of compliance and samples of asphaltic emulsion. Furnish base material that meets the requirements of item 247, flexible base, for the type and grade shown on the plans, before the addition of lime. A telephone with a private line for the exclusive use of the testing facilitys quality control personnel. The mixed material shall be spread and shaped with a mechanical spreader, and compacted with rollers in accordance with. The vertical face may be created by using a header or by cutting back the face to approximately vertical.
Minimizing reflective cracking in cementstabilized. Feasibility study on cement treated base and sub base. Service performance of cementtreated bases as used in. Pdf balancing out materials with concrete is an appealing.
Test cement that has been in storage longer than 6 months by standard mortar tests or loss on ignition test and use. Ctb is made up of insitu soils and aggregates mixed with specific quantities of cement dust. Part of thecivil engineering commons this dissertation is brought to you for free and open access by the iowa state university capstones, theses and dissertations at iowa state. Cement treated base is an ideal solution for outdoor storage lots, parking lots, or industrial aggregate type yards. This guide to ctb discusses its applications, benefits, design, construction, testing, and performance. In concrete pavement, the shrinkage due to hydration and thermal expansioncontraction is typically mitigated with joints and reinforcement. Free reinforced concrete publications notes on aci 31811 building code and simplified design of reinforced concrete buildings eb204. Treated base or soil cement specimens an arizona method 1. Ctb specified as either class a or class b is generally used with asphalt pavements and can be either plantmixed. Cement treated bast ctb is a compacted mixture of graded aggregate, cement, and water, which is used as a base course for the construction of highways, airport runways and taxiways. California department of transportation construction manual july 2019. File all reports, records, charts and diaries developed during the progress of construction activities. The goal of microcracking is to prevent severe, wide cracks from forming and thus reduce the risk of problematic.