This research project evaluated the effect of using recycled aggregate and ground granulated slag on pervious concrete specimens compacted using two different methods: fixed energy and fixed porosity. The permeability, compressive strength, and solar reflectance index were analyzed. When compacted to a fixed target porosity of 20%, mixtures using recycled aggregate had, on average, 12% less strength than virgin aggregate mixtures. The use of slag did not negatively affect permeability, or compressive strength and yet was useful in improving the solar reflectance index in mixtures made with limestone aggregate. Recycled aggregate mixtures exhibited a significantly higher solar reflectance index compared to  the mixtures using virgin aggregates.

Rev. ing. constr.[online]. 2015, vol.30, n.3, pp. 159-167. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732015000300001

Spent fluid catalytic cracking (sFCC) catalyst is a residue that is produced in high volumes by the petrochemical industry and has shown a high potential to be used as a supplementary cementitious material (SCM). This article assesses the sFCC effectiveness as a SCM in mortar based on ordinary Portland cement (OPC), as well as its chemical resistance when the materials are immersed in sulfuric (H2SO4), acetic (CH3COOH) and hydrochloric acid (HCl). The performance of the sFCC was compared to other commercially available mineral additions, such as silica fume (SF) and metakaolin (MK). The results show a mechanical strength increase of up to 17% when the sFCC was included, compared to a control mortar without mineral additions. Immersion in H2SO4 during 90 days led to the formation of gypsum and a loss of chemical resistance up to ~25% in mortars with MK and sFCC. In the samples immersed in HCl, and particularly those made with sFCC and MK, Friedel’s salt was identified due to the ingress of Cl- and the subsequent reaction with the monosulfoaluminates formed during cement hydration.  Immersion in acetic acid led to a loss of strength of up to 57% and 37% in mortars with OPC and sFCC, respectively. Immersion in HCl leads to a stronger attack for blended systems, followed by CH3COOH and H2SO4. The mortar with 20% of sFCC exhibits the best performance, especially in the presence of sulfuric acid.

Rev. ing. constr. [online]. 2015, vol.30, n.3, pp. 169-176. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732015000300002

Rational design for flexible pavement uses fatigue models to determine allowed stresses and deformations in pavement structures which are compared with stresses and deformations calculated with response models. Fatigue models developed for different materials and climatic conditions produce different results. Due to this reason, fatigue models need to be calibrated for local conditions. No pavement fatigue models calibrations have been performed in Colombia. Pavement designers need to use fatigue laws developed for materials and conditions different to national ones, thus creating high uncertainty in the calculated pavement dimensions and long-term performance. The main goal of this research was to evaluate the effect of different fatigue laws used over the final dimensions and construction prime costs of flexible pavements. In order to do this, two pavement structures designed by the rational method were evaluated using the Bisar model and different fatigue laws. As a result, a large variation in costs and dimensions was found, thus confirming that the development and fatigue models calibration may result in significant savings when constructing pavements within the country.

Rev. ing. constr. [online]. 2015, vol.30, n.3, pp. 177-188. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732015000300003

This article has the objective to show a study of different existing theories that consider the friction contribution of embedded piles in rock. It initially summarizes the adopted criteria for such theories and the coefficient ranges considered for the application of their basic expressions. The results of these theoretical analyses were applied in the solution of the foundations of a hotel, and its marine, built on the beach in the city of Varadero, Cuba. The study area presented a high geologic and engineering complexity, with highly variable stratification characteristics together with distinct soil and rock properties, where the presence of a calcareous stratum stands out in the deposit. The calcareous layer is found in a variable depth within the strata and has a quality ranging from very poor to good, where all the pile tips were founded.  In order to obtain the bearing capacities from the designed piles, it was necessary to take into account their friction contribution within the rock, which was done by validating the existing theories through the execution of in situ pile load tests, combined with the use of theoretical models. This exercise allowed the establishment of practical coefficient values that were required by the theories in such particular site conditions.  It was finally possible to yield design solutions for the deep foundations of this case history, which comprised over 2000 driven piles.

Rev. ing. constr. [online]. 2015, vol.30, n.3, pp. 189-199. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732015000300004

Load demands on pavements, due to repeated vehicle loads and environmental conditions, generate a constant deterioration of the structure, which causes the loss of mechanical properties, thereby producing a structural and functional loss on the road. Nowadays, one of the most common problem, which is difficult to control due to these load demands, is reflective cracking, a phenomenon that explains the propagation of existing cracks in lower layers or coinciding with joint movements of an aged pavement, towards the new reinforcement layer, which copies the pathology of the same. The study evaluates the behavior of reflective cracking while varying the location of the geosynthetic material between each asphalt mix layer, and subjecting the system to dynamic loading. The geosynthetic reinforcement considerably delays the progression of the crack, and the greatest effectiveness is obtained when this material is located nearest to the most stressed fiber of the reinforcement layer.

Rev. ing. constr. [online]. 2015, vol.30, n.3, pp. 201-209. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732015000300005

The purpose of an isolation system is to provide an additional means of energy dissipation, thereby reducing the transmitted acceleration into the superstructure. In order to demonstrate the effectiveness of seismic isolation and understand the behavior of seismically isolated bridges a three-span continuous deck bridge made of reinforced concrete is considered. The bridge is modeled as a discrete model and the relative displacements of the isolation bearing are crucial from the design point of view of isolation system and separation joints at the abutment level. The systems presented here are passive control systems and the results of some important experimental tests are also included. The results show that the base shear in the piers is significantly reduced for the isolated system as compared to the non isolated system in the both directions of the bridge. This indicates that the isolation systems are effective in reducing the earthquake response of the bridge.

Rev. ing. constr. [online]. 2015, vol.30, n.3, pp. 210-214. ISSN 0718-5073.  http://dx.doi.org/10.4067/S0718-50732015000300006