• Analysis of high plasticity clayey soil improvement at subgrade level through Portland cement added to decrease volumetric change

      Castro, M. (Institute of Physics Publishing, 2020-02-28)
      This research includes the potential for resistance and the expansion that the soil presents, this evaluation was carried out through CBR tests. The soil cement technique was used to improve the physical and mechanical characteristics; this process consists in mixing the material with Portland cement type I. That combination forms soil cement 10%, 15% y 20%, which present an increase of the CBR (max: 138.7% and min: 91.9%) achieving a type of extraordinary subgrade to resist the structure of the pavement and a reduction of 7.18% in the expansion of the samples.
      Acceso abierto
    • Control of fissures generated by the retraction in rigid pavements, applying synthetic fibers of recycled polypropylene.

      Torres, V. (Institute of Physics Publishing, 2020-02-28)
      The retraction affects the setting process and the useful life of the concrete with the appearance of fissures; in last year's studies and methods have been generated to mitigate and control it with the use of different products and applications. The development of road infrastructure with the use of concrete as a rolling folder, requires methods to guarantee the durability and reduce the effects of the efforts incorporated by the use, climatic conditions, support base and restrictions of movement of the structure. To evaluate the effects of recycled synthetic polypropylene fibers in plastic retraction tests (ASTM C 1579), 3 mix designs were prepared with different ratios 58 gr., 116 gr., and 176 gr. of recycled and virgin synthetic fibers; the most significant and positive result to reduce fissures without affecting the resistance of concrete by bending and compression, was 0.50 mm without addition fibers, 0.10 mm and 0.15 mm with 176 gr. of virgin and recycled synthetic fibers. Finally, it can be concluded that adding a ratio of 4 kg per m3 allows good workability, in addition, the costs of the fibers are not representative compared to the high costs for future repairs.
      Acceso abierto
    • Cracking Control in Mezzanine Floor Slabs using Rice Husk Ash and Polypropylene Fibers

      Cano, B. (Institute of Physics Publishing, 2020-02-28)
      The continuous population increase in recent years requires a greater number of households to be built quickly, with good materials and produced under quality standards that guarantee their manufacturing process. The prefabricated concrete, produced and supplied by concrete plants, is poured into the different structural elements, the mezzanine slabs being the most careful surfaces in the appearance of fissures; because being horizontal and having larger dimensions, the dimensional changes in the concrete appear more frequently due to the rapid loss of water from the surface of the concrete before setting; which generates superior stresses to the resistant capacity of the concrete at early ages, which affect the durability and reduce the resistance of the structures, causing greater economic expenses in maintenance and repairs. In the present investigation, 5%, 10% and 15% of rice husk ash was used as a replacement for cement and 900g/m3 of polypropylene fiber; The results indicate that as the percentage of rice husk ash increases, there is a reduction in the slump and the crack fissures, and that the resistance to compression and flexion decreases, with respect to the concrete pattern.
      Acceso abierto
    • Eco-Concrete for Hydraulic Structures with Addition of Colloidal Nano-Silica

      Salguero, C. (Institute of Physics Publishing, 2020-02-28)
      In the construction of buildings and infrastructures, high resistance materials are used due to current design requirements, concrete being one of the main materials used in the execution of these projects whose cement content is limited to obtaining an economic concrete and of minimum retraction. This limitation requires the use of new additions such as Nano Silica (NS), which due to its nanometric structure is used as a partial replacement for cement, producing an increase in strength in concrete. The present investigation studies the partial replacement of the NS in the cement to determine its behavior in compressive strength, diametric compressive strength, water permeability coefficient. The results indicate that with an addition of 0.225% of NS the compressive strength and splitting tensile strength are increased and the water permeability coefficient decreases, all of them compared to a conventional concrete.
      Acceso abierto
    • Evaluation of the curvature ductility ratio of a circular cross-section of concrete reinforced with GFRP bars

      Pichardo, C. (Institute of Physics Publishing, 2020-02-28)
      The present study deals with the use of fiberglass reinforced polymer bars (GFRP) as a replacement for the common steel of a reinforced concrete circular pile, in order to avoid the corrosion of durability of reinforcing bars and thus improve them. The comparative analysis was carried out between a pile reinforced with GFRP and another with steel, where the ductility was evaluated by obtaining moment-curvature diagram. As a result, said idealized moment-curvature diagrams and ductility indices are presented, concluding the ductility of the section reinforced with GFRP in 20% more than that of steel.
      Acceso abierto
    • Evaluation of the geotechnical behaviour of a volcanic soil wall with additions of lime and cement against landslides

      Davila, C. (Institute of Physics Publishing, 2020-02-28)
      The construction of earth walls can be a significant response to prevent the next landslides from reaching the road and avoid accidents. Therefore, a material of the same slope was used and reinforced with mixtures of lime and cement, with this same reinforced material a mechanically stabilized hypothetical earth wall (MSE) was developed. An analysis of the original slope was developed to check if there was a possible failure through its safety factor. Then, a hypothetical wall was developed with a floor reinforced with mixtures, in order to assess its overall safety factor and its maximum landslides. According to the results, in principle it was determined that the dosage M-3 / C-4-4 improves in a range of 30% to 37% the friction angle. In addition, it was found that a reinforced wall, that is to say with Lime and cement additions, presents a better behaviour. In its effect, its displacements are about 8 mm and have a global factor of 1.23.
      Acceso abierto
    • Experimental analysis of the addition of rice husk ash to the clayey subgrade of a road stabilized with lime

      Vizcarra, S. (Institute of Physics Publishing, 2020-02-28)
      There are many studies about how the addition of lime and rice husk ash (RHA) gives the soil a better mechanical behavior, particularly on clayey soils, where usually fine particles reach more than 75%. However, the soils with a small presence of fine particles (59-60%) do not have much research. This analysis evaluates the influence that RHA has on this kind of soil stabilized with 3% of lime. After the initial mix of soil-lime, CBR increased 11.2 times its initial value; within the addition of the ash, the CBR averaged between 45-50% up until 28% of RHA was added, where the results decreased considerably. Soil workability improved and the specimens with more ash resulted in a more granular material, with a group index value 0 following the AASHTO standards. The greatest CBR record was obtained with the specimen of 16% RHA, 3% lime and soil, reaching a 51.3% CBR, 1.58g/cm3 of MDD and 16.5% of OMC. Yet, it only showed a 1.55% more resistance than the lime-soil specimen. The CBR with more presence of RHA tends to decrease its value, therefore for silica-rich clayey soils, the addition of lime by itself should be enough for an adequate performance.
      Acceso abierto
    • Experimental study of the mechanical effect of a clayey soil by adding rubber powder for geotechnical applications

      Alvarez, N. (2020-02-28)
      At present, worrying quantities of tires are discarded due to the growth in demand for vehicles in the world, which has a direct impact on the deterioration of the environment since they normally go to landfills. Based on the background found, the use of this material for geotechnical applications can help reduce the pollution they generate and improve the physical and mechanical properties of soils. Therefore, this research seeks to evaluate a greater shear strength and capacity of support to the penetration of the clayey soil by means of the addition of 1.5%, 2.5% and 3.5% of rubber powder recycled. For this, the Atterberg limits analysis, the modified proctor compaction test, shear box and CBR were performed. For the shear box test, the results reflect that the cohesion of the mixture increased and the angle of internal friction decreased with respect to the natural soil, resulting in the sum in an increase of shear strength. On the other hand, the percentage of CBR increased, this means that the rubber helped the soil to be more rigid and have a greater resistance to penetration. These mixtures could be used in different projects within geotechnical engineering, as it presents an improvement in shear strength and an acceptable support index value (CBR).
      Acceso abierto
    • Improvement of physical, mechanical and strength behavior of cohesive soils with natural pozzolana and brick dust

      Chang, E. (Institute of Physics Publishing, 2020-02-28)
      This research project seeks to improve soil properties through experimentation with geotechnical purposes. For this, will be used natural volcanic pozzolana in 5%, 10%, 15% and brick dust in 10% giving it a second reuse. The soil improvement will be analyzed with the proposed additions and its influence on the results. It is concluded that the addition improves the behavior of the soil by decreasing its plasticity index, increases the compaction index and improves the geotechnical parameters.
      Acceso abierto
    • Low Permeability Concrete for Buildings Located in Marine Atmosphere Zone using Clay Brick Powder

      Castillo, M. (Institute of Physics Publishing, 2020-02-28)
      The concrete is not one hundred percent impermeable since the water that remains inside it causes its corrosion, in the case of reinforced concrete, exposed in an area of marine atmosphere, the sea salt mostly present in large particles of the marine spray, produce the reduction of the alkalinity of the concrete causing a rapid corrosion of the steel. There are buildings built in this marine area that have been designed without durability criteria, in which the use of pozzolanic materials is considered, for example, to fill the pores of the cement matrix and thus guarantee its impermeability. In the present study, the effect of clay brick powder (PLA) as a replacement for cement in concrete manufacturing is addressed, evaluating different characteristics of its components. The results indicate that pozzolanic activity and compressive strength increase, slump, voids content and the coefficient of permeability to water decreases.
      Acceso abierto
    • Mechanical properties and self-cleaning mortar capacity C/A 1: 5 of Portland cement modified with titanium dioxide (TiO2)

      Flores, H. (Institute of Physics Publishing, 2020-02-28)
      The deterioration of the surfaces of the constructions made with mortar C/A 1: 5 of Portland cement, are produced by being exposed to the emission of toxic gases emanating from the growing automobile fleet, this problem causes alternatives to be sought in order to counteract its effect on buildings and the environment. A new method to deal this problem is the incorporation of the titanium dioxide photocatalyst (TiO2) into the Portland cement mortar, which can develop self-cleaning and air purification properties to be in contact with sunlight. This work seeks to introduce this organic component to the Portland cement mortar, used for the facade charging and structural elements, for this purpose, different percentages (5%, 7.5% and 10%) of titanium dioxide (TiO2) are added and the properties of the modified mortars making use of [1] compression tests, [2] fluidity tests, [3] absorption tests and [4] photocatalytic activity tests with which the self-cleaning capacity was verified. This study concludes that the best percentage of titanium dioxide addition is 5%, with which the Portland cement mortar is granted self-cleaning property without substantially damaging its mechanical properties.
      Acceso abierto
    • Mechanical Properties of an Eco-friendly Concrete with partial replacement of POC and Rubber

      Espinoza, A. (Institute of Physics Publishing, 2020-02-28)
      Concrete plants consume 10 billion tons of natural aggregates annually from quarries and gravel plants for produce concrete, this demand requires exploiting natural resources from mountains and rivers producing an ecological imbalance. One solution is to use Palm Oil Clinker (POC), which is eliminated in large quantities in the dumps and rivers without taking advantage of its puzolanic, binding and resistance properties as an aggregate in the concrete; another alternative is to apply rubber from abandoned and discarded tires as waste in landfills or burned, without taking advantage of its performance of improvement in concrete, increasing its resistance to impact and fatigue. Unable to find joint POC and rubber information, this research studies its influence replacing 2.5% rubber (grained and crushed) with 10%, 12.5% and 15% POC in the fine aggregate on traditional concrete; results indicate that with 12.5% of POC as the ideal percentage, the compressive strength, tensile strength and flexural strength rise between 2.16 - 9.54%, so the concrete obtained has a cost of less than 4.09% and has 3.65% less CO2 emission.
      Acceso abierto
    • Methodology for determining optimized traffic light cycles based on simulation

      Rivera, G. (Institute of Physics Publishing, 2020-02-28)
      In large urbanized cities, a major problem that affects the economy and health of all citizens is vehicular congestion. This is because the traffic light cycles are not adequate. In the present study, we seek to optimize traffic light cycles based on simulation, in order to improve vehicle flow. For this, the PTV Vissim 9.0 software was used as a simulator and the Synchro 10.0 software to determine the initial optimal traffic light cycle. Through several runs and having as variables the length of queues, delay times and the average speed, the optimal traffic light cycle could be found for the study area. The results obtained reflect a 14% reduction in delay times and 10% in queue lengths. On the other hand, the average vehicle speed increased by 10.56%. All this represents an improvement in the service level of the study intersections.
      Acceso abierto
    • Productivity improvement of tower crane in tall buildings

      Manrique, A. (Institute of Physics Publishing, 2020-02-28)
      The tower crane is an electromechanical equipment that is used for the vertical transport of materials in a construction project and together with the two riggers form the work team to carry out this task. One of the main problems in the construction of multifamily buildings corresponds to the use of the tower crane because vertical transport causes non-contributory times, which is, dead times and waits above expectations. This research analyzes the current vertical transport process and proposes its optimization through some management tools with the aim of improving the productivity of the use of the tower crane by reducing non-contributory times. To this end, the productivity of the work team is recorded in several projects with similar characteristics, then the main problems are selected to analyze them and finally the process is optimized. The results determined that non-contributory times can be reduced by 10% if there is an orderly and continuous process.
      Acceso abierto
    • Proposal of Flowable Fill Designs for improvement of excavation and filling works of trenches in sanitation systems

      Cruz, J. (Institute of Physics Publishing, 2020-02-28)
      Population grow in recent years requires an extension of the current pipeline sanitary system. For this purpose, granular excavation and landfill works are associated with pedestrian traffic congestion. Therefore, it is necessary to develop an innovative and sustainable alternative to reduce the problems generated during the execution of the conventional process. This research proposes the use of flowable fill due to the multiple advantages offered by this material. On the one hand, it is economical for medium to large trench fill volumes, considering savings in labor (it is done with a small number of workers), in equipment (does not require the rental or purchase of compaction equipment) and in time (the pouring is done by directly pumping the mixture, from the mixing machines to the excavation). On the other hand, being self-compacting and self-leveling decreases the width of the trenches, reducing excavation and filling volumes; which, in turn, incur money savings. Also, this material guarantees work safety, since people are not required inside the excavation and fill in poorly accessible areas without any problem. Dosages were established for ten flowable fill mixtures with cement contents of 50, 60, 70, 80 and 90 kg of cement and a range of admixture from 1.75 to 2.00%; The results indicated that decreasing the fine aggregate - coarse aggregate ratio, the compressive strength of the mixtures increases and the slumps of the mixtures decreases, and the compressive strength increases directly proportional to the cement content.
      Acceso abierto
    • Stabilization of a Subgrade Composed by Low Plasticity Clay with Rice Husk Ash

      Ormeno, E. (Institute of Physics Publishing, 2020-02-28)
      The construction of road works in the world has always been a challenge for engineering, especially in areas where the conditions and types of soil are not adequate for the execution of this type of projects. The present investigation has as main objective to determine the influence that has the rice husk ash (RHA) to stabilize the subgrade layer of a pavement, composed of a low resistance clayey soil. RHA is a waste and pollutant material for the environment; therefore that its use can be considered as an economic and ecological alternative. Thus, several tests were carried out where it proved the value of CBR increased from 4.30% to 20.70%, by adding a 20% RHA dosage, achieving its optimum value to be considered a very good subgrade. In this way, it is possible to affirm that the addition of RHA improves the geotechnical properties of the soil.
      Acceso abierto
    • Stabilization of clayey soil for subgrade using rice husk ash (RHA) and sugarcane bagasse ash (SCBA)

      Hidalgo, F. (Institute of Physics Publishing, 2020-02-28)
      This document studies the stabilization of the soil used as a subgrade, by adding locally available materials such as rice husk ash (RHA) and sugarcane bagasse ash (SCBA). These aggregates were added to the soil in substitution by weight between 5%, 7.5% and 10%. By adding these, the expansiveness is reduced while the maximum dry density increases, in addition the tendency of CBR is increasing and then tends to decrease proportionally to the addition of the aforementioned aggregates. This indicates a peak in CBR and expandability. The best result obtained from CBR was 33.75% with the 5% replacement mixtures.
      Acceso abierto
    • Theoretical design proposal for simulated hot asphalt mixture at a temperature below zero degrees Celsius

      Chávez, H. (Institute of Physics Publishing, 2020-02-28)
      In the world there are adverse climates, climates that hinder the good construction and paving of roads, generating insecurity among the locals and visitors. This over time affects the economy of a country, as a road boosts tourism, transport and commerce. Therefore, a mixture was designed to mitigate a problem in the placement of hot asphalt mixture at temperatures below zero degrees Celsius. That is, a conventional mix design was proposed, but with different types of filler (lime, Portland cement type I and silica) tested with the Marshall and Lottman method which are governed according to the EG-2013 standards [1] and parameters established in the Asphalt Institute [2]. To find the optimum, it was tested with 5.0%, 5.5% 6.0% and 6.5% asphalt cement. Then with the results obtained a comparative analysis was performed. Finally, specimens without any additives were made, the specimens once prepared at 140°C were subjected to freezing, resulting in the three types of filler, that the hot asphalt mixture with incorporation of Portland cement type I to a 5, 90% of asphalt cement is the optimum since, subject to extreme temperatures below 0°C they comply with the parameters required in the standards.
      Acceso abierto
    • Use of recycled broken bricks as Partial Replacement Coarse Aggregate for the Manufacturing of Sustainable Concrete

      Pinchi, S. (Institute of Physics Publishing, 2020-02-28)
      The bricks are one of the primary materials required for construction of homes that no used completely when executes all the walls due, the excess purchase, the cutting to be settle, the breaking for their transfer and its fixed dimensions; this situation requires monitoring on work site the order, cleanliness and accidents. A common practice is these bricks and/or waste are included in the clearing construction before being deposited or eliminated in dumps or sanitary landfills, with their early clogging and shortening them to ther design lifespan. An important alternative to reduce this waste, is to recycle them and reuse them as a concrete component material, due to their high absorption percentage that allows them to keep the water inside of them and then use it in the cement hydration process as internal curing of the concrete. In the present investigation, the effect of crushed clay brick as a replacement for coarse aggregate in concrete processing is studied. The results indicate that with 21 % replacement brick, the plastic contraction decreases, and the compressive strength and flexural strength increase.
      Acceso abierto