Concrete properties such as unit weight and compressive strength are highly dependable on the properties of aggregate. Current research aims to study the effect of aggregate properties on concrete considering the reso...Concrete properties such as unit weight and compressive strength are highly dependable on the properties of aggregate. Current research aims to study the effect of aggregate properties on concrete considering the resource of aggregate. The properties of aggregate and fine sand were studied (specific gravity, density, absorption, and abrasion). Also, the properties of concrete were studied (density, unit weight, and compressive strength). Samples of coarse and medium aggregates, and fine sand were collected from different areas in Jordan (Ajloun, Amman, Aqaba, Irbid, Jerash, Karak, Ma’an, Madaba, Salt, Zarqa, and Tafila) to be tested and used in concrete mix. Aggregate from South of Jordan has higher values in specific gravity and bulk density (Aqaba, Ma’an, and Karak aggregates). Also, the same aggregate samples have lower values in absorption and abrasion (Ma’an, Aqaba, Karak, and Tafila). For the properties of concrete that include density, unit weight, and compressive strength, all samples have achieved the design properties and strength in the current study. For density and unit weight, samples from South of Jordan have higher values (Ma’an and Aqaba). And for compressive strength, Ma’an, Irbid and Amman concrete samples have the highest values at 7-day, while the 28-day compressive strength comes highest for Zarqa, Ma’an, Irbid and Amman. From the results of the current study, the compressive strength at 7-day and 28-day is related to the density of coarse and medium aggregate, abrasion, and absorption. The higher the density, the higher the compressive strength. And the lower abrasion and absorption, the higher the compressive strength of concrete. Current research will be useful in selecting the source of aggregate to produce a considerable concrete strength.展开更多
A recycled aggregate(RA)was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties.On this basis,pervious concre...A recycled aggregate(RA)was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties.On this basis,pervious concrete(PC)mix proportions were designed.Coarse RA particles with sizes of 5–10 and 10–20 mm were selected.Concrete specimens were prepared with a water–cement ratio of 0.3,an aggregate–cement ratio of 4.5,the substitute rates of RA with 0,25%,50%,75%and a single-/double-gap-graded RA mix(mass ratio of particles with sizes of 5–10 mm to particles with sizes of 10–20 mm:1:1,1:2,2:1,2:3 and 3:2).Various properties of the RA-containing PC(RPC)were determined by analyzing the compressive strength,splitting tensile strength,effective porosity,permeation coefficient and impact and abrasion resistance of the specimens.The results showed the following:The density of the RPC decreased with an increasing RA replacement ratio.The density of the RPC prepared with a double-gapgraded RA mix was lower than that prepared with a single-gap-graded RA(particle size:10–20 mm)mix.The permeation coefficient of the RPC increased with increasing porosity.The splitting tensile strength of the RPC was positively correlated with its compressive strength.The compressive strength of the RPC decreased with increasing porosity.The regression analysis showed that the impact and abrasion resistance of the RPC increased with increasing compressive strength.In addition,all of the RPC specimens met the strength and permeation requirements.This study can provide theoretical support for the application of RPC.展开更多
文摘Concrete properties such as unit weight and compressive strength are highly dependable on the properties of aggregate. Current research aims to study the effect of aggregate properties on concrete considering the resource of aggregate. The properties of aggregate and fine sand were studied (specific gravity, density, absorption, and abrasion). Also, the properties of concrete were studied (density, unit weight, and compressive strength). Samples of coarse and medium aggregates, and fine sand were collected from different areas in Jordan (Ajloun, Amman, Aqaba, Irbid, Jerash, Karak, Ma’an, Madaba, Salt, Zarqa, and Tafila) to be tested and used in concrete mix. Aggregate from South of Jordan has higher values in specific gravity and bulk density (Aqaba, Ma’an, and Karak aggregates). Also, the same aggregate samples have lower values in absorption and abrasion (Ma’an, Aqaba, Karak, and Tafila). For the properties of concrete that include density, unit weight, and compressive strength, all samples have achieved the design properties and strength in the current study. For density and unit weight, samples from South of Jordan have higher values (Ma’an and Aqaba). And for compressive strength, Ma’an, Irbid and Amman concrete samples have the highest values at 7-day, while the 28-day compressive strength comes highest for Zarqa, Ma’an, Irbid and Amman. From the results of the current study, the compressive strength at 7-day and 28-day is related to the density of coarse and medium aggregate, abrasion, and absorption. The higher the density, the higher the compressive strength. And the lower abrasion and absorption, the higher the compressive strength of concrete. Current research will be useful in selecting the source of aggregate to produce a considerable concrete strength.
基金This study was funded by the National key research and development program fund project(No.2018YFC0406803).
文摘A recycled aggregate(RA)was prepared by crushing and sieving demolished discarded concrete pavements and was subsequently tested and analyzed to determine its various physical properties.On this basis,pervious concrete(PC)mix proportions were designed.Coarse RA particles with sizes of 5–10 and 10–20 mm were selected.Concrete specimens were prepared with a water–cement ratio of 0.3,an aggregate–cement ratio of 4.5,the substitute rates of RA with 0,25%,50%,75%and a single-/double-gap-graded RA mix(mass ratio of particles with sizes of 5–10 mm to particles with sizes of 10–20 mm:1:1,1:2,2:1,2:3 and 3:2).Various properties of the RA-containing PC(RPC)were determined by analyzing the compressive strength,splitting tensile strength,effective porosity,permeation coefficient and impact and abrasion resistance of the specimens.The results showed the following:The density of the RPC decreased with an increasing RA replacement ratio.The density of the RPC prepared with a double-gapgraded RA mix was lower than that prepared with a single-gap-graded RA(particle size:10–20 mm)mix.The permeation coefficient of the RPC increased with increasing porosity.The splitting tensile strength of the RPC was positively correlated with its compressive strength.The compressive strength of the RPC decreased with increasing porosity.The regression analysis showed that the impact and abrasion resistance of the RPC increased with increasing compressive strength.In addition,all of the RPC specimens met the strength and permeation requirements.This study can provide theoretical support for the application of RPC.
