Papers by Deb Dulal Tripura
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Lecture notes in civil engineering, Dec 1, 2022
Proceedings of the Institution of Civil Engineers - Forensic Engineering
This paper deals with the validation of a cob sample production technique that replicates the on-... more This paper deals with the validation of a cob sample production technique that replicates the on-site wall construction method. Cob cubes were prepared under confined and unconfined conditions with varying drop heights (0.50, 0.75 and 1.00 m) and moulding water contents (25.7–39.7%) by mass of soil. Prior to mass production of samples, a trial test was performed at a constant drop height of 0.75 m and varying water contents. Based on the trial test results, the other two drop heights of 0.50 and 1.00 m were adopted for further validation. The effects of confinement, drop height and moulding water content on the compressive strength and density of cubes were studied. Test results show maximum compressive strengths and densities ranging from 1.22 to 1.31 MPa and 1.65 to 1.70 g/cm3, respectively, at a 33.7% water content and a 0.75 m drop height, with those for the confined specimen being the highest. The strength and density values obtained satisfy the guidelines prescribed by some st...
Journal of Building Engineering
Materials and Structures, 2022
This paper investigates the effect of coir along with bamboo and steel reinforcement on the flexu... more This paper investigates the effect of coir along with bamboo and steel reinforcement on the flexural strength and failure patterns of cement stabilized rammed earth wallettes. About 10% cement was used as stabilizer and 1% coir of 25 mm length along with bamboo or steel was used as reinforcement for rammed earth wallettes production. To study the bond strength between rammed earth and reinforcement, 20 rammed earth blocks were prepared with bamboo and steel reinforcement and to study the flexural strength of rammed earth wallettes 36 samples were prepared in two categories. First category consists of vertical samples of size 600 mm $$\times$$ × 230 mm $$\times$$ × 120 mm (height/length $$\times$$ × Width $$\times$$ × thickness) and second category consists of horizontal samples of size 230 mm $$\times$$ × 600 mm $$\times$$ × 120 mm (height/length $$\times$$ × width $$\times$$ × thickness). The test results show that coir reinforcement improved the bond strength and the highest bond strength was obtained with coir and steel reinforced rammed earth blocks. Coir along with bamboo or steel reinforcement increased the flexural load carrying and lateral deflection capacity of the samples by about 13.42–154.88% and 33.78–76.12% respectively. Rammed earth samples undertake 42.59–63.30% more flexural stress when tested perpendicular rather than parallel to the ramming layers. The current technique of reinforcing cement stabilized rammed walls with coir along with bamboo or steel can be used for constructing internal and external load bearing walls in single or two storey rammed earth houses considering the seismic zone of the area. To predict the ultimate load carrying and lateral deformation capacity of samples, a series of regression analysis was performed using the test data correlating the reinforcement type and loading conditions. With coefficient of correlation R 2 > 0.78, the equations obtained from the analysis represent a strong relation between the actual measured and predicted values.
Journal of Building Engineering
Lecture Notes in Civil Engineering, 2019
Mud earth blocks are green constructional materials with zero carbon footprints, low embodied ene... more Mud earth blocks are green constructional materials with zero carbon footprints, low embodied energy, economical, etc., but having low compressive as well as least tensile strength and subjected to high shrinkage. This paper presents an experimental study on the behavior of mud earth blocks reinforced with natural fiber. The test blocks were prepared by adding 5% coir fiber by weight of dry soil as reinforcing material with varying sizes ranging from 2 to 8 cm. The effect on properties like shrinkage, compressive and tensile strength, cracking time, and failure pattern due to the presence of fiber were studied in comparison to unreinforced mud earth blocks. The test results showed that the mechanical properties of the blocks are highly affected by the fiber length. Compressive and tensile strength of the blocks with fiber length 4 cm gave the maximum results about 1.45 times and 4 times than that of unreinforced blocks, respectively. Thus, 4 cm length size fiber reinforced mud earth...
This paper investigates the effect of aggregate inclusion on the properties of rammed earth block... more This paper investigates the effect of aggregate inclusion on the properties of rammed earth blocks in terms of strength, and durability followed by predicting the compressive and tensile strengths based on ultrasonic pulse velocity (USPV), maximum dry density (MDD), Young’s modulus (E) and aggregate content (Agg) using linear and non-linear statistical regression analysis. Natural and fresh brick aggregates of size 4.75 mm−10 mm were used varying from 0% to 30% by mass of dry soil and 10% of cement as stabilizer. The investigation shows that the compressive and tensile strength increases up to 20% aggregate content followed by reduction in strength. All the aggregate induced blocks meet the durability criteria specified by some standards and researchers. The blocks with natural aggregate exhibits superior performance than brick aggregate in terms of strength and durability. A series of regression equations are developed separately for natural and brick aggregate blocks from the stat...
In order to minimize the environmental impacts caused by over exploitation of natural resources f... more In order to minimize the environmental impacts caused by over exploitation of natural resources for the production of building material, the possibility of using blended soil blocks duly burnt for load-bearing walls has been assessed to alternate the fertile top soil of agricultural land. Since the vertical load carrying capacity primarily depends on the compressive strength, a comprehensive study was conducted for burnt soil blocks made with commonly available laterite and clay soil types in Tripura (India). The results indicate the possibility of using burnt soil blocks for single storey houses which may also be extended to two storey houses.
Advances in Structural Engineering
In this article, the effect of weathering and corrosion on the bond properties of bamboo- and ste... more In this article, the effect of weathering and corrosion on the bond properties of bamboo- and steel-reinforced cement-stabilized rammed earth blocks was investigated. The treated, untreated bamboo and steel reinforcement types were considered under regular and weathered categories. Reinforcement of 8 mm, 10 mm and 12 mm diameters were used along with 10% of cement as stabilizer. A total of 90 reinforced cement-stabilized rammed earth blocks were prepared and tested for bond strength. The investigation shows that the bond force and bond strength of all the blocks reduced due to weathering and corrosion of reinforcement. In case of blocks with bamboo reinforcement only, a minor reduction in bond properties (bond force and bond strength) was identified, but in case of blocks with steel reinforcement, a major reduction in bond properties was identified. All the blocks failed by either lateral splitting, pullout or pullout along with lateral splitting. However, the pullout failure was ob...
vii Abstract The present study aims to determine the suitability of locally available soil (Agart... more vii Abstract The present study aims to determine the suitability of locally available soil (Agartala, India) for the production of cement stabilised ramm ed earth (CSRE) columns with a proposed CSRE specimen making technique, followed b y investigations on the effects of (1) slenderness ratios on the axial column stren gths of both unreinforced rectangular and circular CSRE columns, (2) cross-se ctional aspect ratios on unreinforced rectangular CSRE columns, and (3) late ral steel reinforcement ratios for CRSE columns longitudinally reinforced with steel a nd bamboo splints. The properties of locally available soil and its suitab lity was determined in terms of density, strength, compaction energy and durability n both cured and uncured conditions using the proposed block-making equipmen t and technique. Test result shows that the average characteristic strength of c ured samples is about two times higher than that of uncured samples. The compressiv strength and density of CSRE bloc...
Proceedings of the Institution of Civil Engineers - Structures and Buildings
In the present study, a novel experimental programme is conducted to evaluate the compression and... more In the present study, a novel experimental programme is conducted to evaluate the compression and shear behaviour of cob wallettes reinforced with bamboo and steel mesh. Three major categories of wallettes were prepared comprising at least three samples for each type for both compression and shear tests. The first category comprises four types of samples: unstabilised, unreinforced cob wallettes (USURCWs), cement-stabilised cob wallettes (CSCWs), coir-fibre-reinforced cob wallettes (CFRCWs) and straw-fibre-reinforced cob wallettes (SFRCWs). In the second and third categories, similar sample types as included in the first category were reinforced with bamboo and steel mesh, respectively. Five per cent fibres and 10% cement (by dry mass of soil) was added to the respective dry soil mixes followed by addition of 33.7% water and thorough mixing. Test results showed that the addition of fibre, cement and bamboo or steel reinforcement prevents brittle failure. Fibre-reinforced samples sho...
Materiales de Construcción
This paper presents an experimental study on the behavior of cement stabilized rammed earth (CSRE... more This paper presents an experimental study on the behavior of cement stabilized rammed earth (CSRE) column reinforced with steel under axial loading and its comparison with unreinforced and bamboo reinforced columns. Effects of structural parameters such as tie / stirrup spacing on the failure pattern, lateral and axial deformation of columns are studied. Test results show that the load-capacity of columns increases with increase in lateral / tie reinforcement ratio. Maximum axial and lateral deformations occur in columns with least tie spacing. Behavior of CSRE columns reinforced with close tie spacing is characterized by gradual spalling of cover at the failure zone. Steel reinforced columns perform better than other column types in terms of load-capacity; hence it may be used as structural member adjacent to walls for low-rise rammed earth houses. Proposed reinforcement technique can be adopted in the field for enhancement of greater strength and performance of columns.
Construction and Building Materials
Construction and Building Materials
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Papers by Deb Dulal Tripura