Aggregate suitability and Geo-chemical investigation of limestone for construction industries in Pakistan: An approach for economic development

This study investigated the aggregate suitability and geo-chemical characteristics of limestone (LS) for construction industries. The results of aggregate parameters for different applications revealed that specific gravity (SG = 2.6), water absorption (WA = 0.47%), bulk density (BD = 1.58 g/cm3), flakiness index (FI = 16.8%), elongation index (EI = 16.39%), soundness (S = 1.6%), aggregate impact value (AIV = 14%), Los Angles Abrasion value (LAAV = 23.51%), clay lumps (CL = 0.35%), uniaxial compressive strength (UCS = 86.7 MPa), point load test (PLT = 5.18 MPa), ultrasonic pulse velocity (UPV = 5290 m/s) and Schmidt hammer rebound test (SHRT = 49 N) are in accordance with ASTM, ISRM and BSI. Petrographically, the LS is dominantly composed of ooids, peloids, bioclasts and calcite (CaCO3) with trace concentration of the dolomite. Geochemical results (n = 18) indicated that the LS is dominantly made up of calcite (95.81%); while on average it is composed of 52.08 wt.% CaO, 1.13 wt. % SiO2, 0.66 wt. %, MgO, 0.80 wt. % Al2O3, 0.76 wt. % Fe2O3 and LOI were recorded as 42.13 wt. %. Whereas, P2O5, TiO2, MnO, K2O and Na2O are found in trace amount. Regression analysis demonstrates that the empirical correlation equation for estimating uniaxial compressive strength with ultrasonic pulse velocity is more reliable than Schmidt hammer rebound test and point load test. The findings of this study strongly suggest LS of the area has a great potential as a raw material in construction industries.

Characterization of rock material by point load strength index test and direct cut

The objective of this work is to establish a relationship between the cutting time in rocks, determining a speed and the point load strength index test, Is (50), to characterize the rock in terms of resistance and avoid sending samples to laboratories. As a first stage, on andesite samples, 5 x 5 x 10 cm test tubes were made. After the elaboration they were subjected to cutting, using an electric floor cutter and the time was evaluated. This cut was made in a transversal way and two parts were obtained, one of them with dimensions 5 x 5 x 5 cm, approximately. In a third stage, the point load strength test was carried out in a press built for this purpose. Finally, the cutting speeds were correlated with the point load test values and only when rock samples do not pigeonhole on the proposed relationship, send them to the laboratory. Keywords: Mining fortification, uniaxial compressive strength, rock cutting, point load strength test index. References [1]P. Feijoo, R. Aucay, D. Ordoñez, "Aplicación del esclerómetro para la determinación de resistencia a compresión de rocas", presentado en el IV Congreso Internacional de Minería y Metalúrgia (MINEMETAL), Varadero, Cuba, 2018. [2]P. Feijoo y M. Román, «Correlación entre la Deformación y la Resistencia a la Compresión de rocas», uct, vol. 23, n.º 91, p. 6, may. 2019. [3]P. Feijoo, A. Bravo, N. Escandón, "Aplicación “UDAFORMIN” para la determinación del tipo de fortificación minera", presentado en el XII Congreso Iberoamericano de Computación para el Desarrollo (COMPDES), San Salvador, El Salvador, 2019. [4]P. Feijoo y C. Iñiguez, «Corte en las Rocas y su Relación con la Resistencia a Comprensión Simple», RISTI, n.º E 30, p. 59-67, jun. 2020. [5]P. Feijoo y J. Padrón, «La Resistividad de Rocas y su Relación con la Resistencia a Comprensión Simple en Mina», UCT, vol. 24, n.º 99, pp. 61-67, abr. 2020. [6]M. González. El terreno. Ediciones UPC. Barcelona. España, 2001. [7]E. Besoain. Mineralogía de Suelos. Turrialba: Instituto Interamericano de Ciencias Agrícolas de la OEA, 1970. [8]P. Feijoo, A. Flores, B. Feijoo, "The Concept of the Granulometric Area and Its Relation with the Resistance to the Simple Compression of Rocks", presentado en la 7th International Engineering, Sciences and Technology Conference (IESTEC), Panamá, Panamá, 2019, pp. 52-56, doi: 10.1109/IESTEC46403.2019.00018. [9]F. Blyth. Geología para Ingenieros. Cecsa. México D. F. México, 2003. [10] E. Tarbuck & F. Lutgens. Ciencias de la Tierra: Una introducción a la Geología Física. Pearson. Madrid. España, 2005. [11]L. Suarez del Rio, A. Rodríguez, L. Calleja, V. Ruiz de Argandoña, «El corte de rocas ornamentales con discos diamantados: influencia de los factores propios del sistema de corte», CSIC, vol. 48, n.º 250, pp. 53-59, abr-mayjun 1998. [12]Universidad Politécnica de Madrid. Explotaciones de Roca Ornamental. Diseño de explotaciones y selección de maquinaria y equipos. UPM. Madrid. España, 2007. [13]Catalog, Covington, (2019). LAPIDARY & GLASS MACHINERY, USA. Retrieved from https://covington-engineering.com/content/pdf/Covington-Catalog.pdf. [14]D. Burbano, T. García, «Estimación empírica de la resistencia a compresión simple a partir del ensayo de carga puntual en rocas anisótropas (esquistos y pizarras)», FIGEMPA, vol.1, n.º 2, pp. 13-16, dic. 2016. [15]P. Ramírez, L. de la Cuadra, R. Lain, E. Grigalbo. Mecánica de rocas aplicada a la minería metálica subterránea. Instituto Geológico Minero. Madrid. España, 1984. [16]P. Cordero, "Manual de prácticas de laboratorio de Mecánica de Rocas (Parte I)" tesis, Universidad Nacional Autónoma de México, México D.F., México, 2019. [17]L. González de Vallejo, M. Ferrer. Manual de campo para la descripción y caracterización de macizos rocosos en afloramientos. Instituto Geológico y Minero de España. Madrid. España, 2007. [18]P. Pohjanpera, T. Wanne, E., Johansson. Point Load Test Results From Olkiluoto Area Borehole Cores. Posiva. Finlandia, 2005. [19]P. Ramírez, L. Alejano. Mecánica de rocas: fundamentos e ingeniería de taludes. Universidad Politécnica de Madrid. Madrid. España, 2004. [20]M. Navarrete, W. Martínez, E. Alonso, C. Lara, A. Bedolla, H. Chávez, D. Delgado, J. Arteaga. «Caracterización de propiedades físico-mecánicas de rocas ígneas utilizadas en obras de infraestructura», ALCONPANT, vol. 3, n.º 2, pp. 133-143, ago. 2013. [21]P. Feijoo, "Manual de mecánica de rocas y estabilidad de túneles y taludes" tesis, Universidad del Azuay, Cuenca, Ecuador, 1997.

Performance of Reinforced Concrete Beam with Polystyrene Blocks at Various Regions

Lightweight materials, such as polystyrene, can be embedded in reinforced concrete (RC) beams to reduce its weight. However, this may, to some extent, affect the performance of the structure. This research investigates the behaviour of the lightweight beams under load and determines the best position of polystyrene blocks in beams. Nine specimens with a size of 175 mm x 300 mm x 1600 mm were tested under four-point load test. The number and position of polystyrene blocks in the beams were varied. The specimens were evaluated for effectiveness in terms of effective strength to weight ratio (s-w ratio). The lightweight beam was effective when the polystyrene blocks were placed at the neutral and tensile region, offering an s-w ratio of greater than 1. The beam lost 3.8% strength with 8.4% reduction of weight.